Evidence preservation in patent infringement suits in China

By Chen Jian, Sanyou Intellectual Property Agency
Copy link

How to obtain evidence has always been a problem facing plaintiffs in patent infringement suits. This difficulty is particularly pronounced in the case of infringing products that have specific sales channels or sales markets.

陈坚 CHEN JIAN 三友知识产权代理有限公司 合伙人 Partner Sanyou Intellectual Property Agency
Sanyou Intellectual
Property Agency

For example, when an alleged infringing product is a large piece of industrial machinery or equipment, it is impossible for the patent holder to secure evidence through commercial purchase on the market. Lawyers need to formulate a tailored evidence-gathering plan based on the actual circumstances of the case. In this column, the author discusses the application of evidence preservation in patent infringement suits.


The term “evidence preservation” means the act by a court to investigate, collect, fix and protect evidence pursuant to an application or ex officio, where such evidence could be destroyed or lost, or be difficult to secure in future.

Article 81 of the Civil Procedure Law improves the framework of China’s evidence preservation system, specifying that, “In urgent circumstances, where evidence could be destroyed or lost, or be difficult to secure in future, a materially interested person may apply for evidence preservation to the People’s Court of the place where the evidence is located, the place where the respondent is domiciled or the competent People’s Court in the case before he/she institutes a legal action or applies for arbitration”.

The judicial interpretations for the Civil Procedure Law add greater detail to the above-mentioned. Courts in various places, such the Beijing High Court, Shanghai High Court, Zhejiang High Court, etc., have all formulated more specific regulations.


Based on current laws and practice, courts have a number of means available to them to preserve evidence, including: placing under seal, or seizing dies, machinery and equipment used specifically to produce the alleged infringing product, and taking photographs or video of such dies, machinery and equipment; inventorying or placing under seal the stock or quantity of finished or semi-finished alleged infringing products; taking copies of or seizing financial account books or statements, production records, warehouse records, sales contracts, quotes, sales invoices, etc., that can reflect the quantity and amount of, and profit from, the production or sale of the alleged infringing product; taking or seizing samples of the alleged infringing product and related publicity materials, brochures, and product lists; taking copies of alleged infringing programs, images, corresponding technical parameters, materials and other such technical information, as well as internal management information and customer information stored in computers and other data storage devices.

Just the above-mentioned means of evidence preservation can satisfy the needs of a patent infringement suit. Counsel should apply for the suitable means of evidence preservation based on the actual circumstances of the case.


The principle applied by courts in handling evidence preservation is to prudently exercise their discretion with respect to “evidence could be destroyed or lost, or be difficult to secure in future”, not only fully taking into consideration the instability and destructibility of intellectual property evidence so as to promptly and effectively take preservation measures, but also preventing parties from abusing the evidence preservation procedure, shifting the burden of proof and wasting judicial resources.

It is necessary to profoundly understand this principle, duly carry out the relevant work and fully prepare before submitting an application for evidence preservation, so as to convince the court to approve the evidence preservation and enhance the chance of making a successful evidence preservation application.

  1. It is necessary to explain why the case in question falls into the category of one in which “evidence could be destroyed or lost, or be difficult to secure in future”. Counsel needs to explain the necessity of carrying out evidence preservation in the case. For example, based on commercial trading practice, it is impossible to notarize the purchase of a large piece of equipment, the alleged infringing product is located in a closed factory, the reason and evidence for the defendant refusing to trade, etc.
  2. A detailed technical explanation and infringement comparison are helpful in increasing the court’s inward confirmation. The patent holder should carry out a detailed infringement comparison, explaining the high probability that the alleged infringing product is infringing. In cases in which the probability of prevailing is low, judges will usually refuse to support evidence preservation.
  3. Sufficient preliminary evidence must be available. Evidence preservation is not evidence for which the patent holder is waiting for the court to provide evidence preservation. The patent holder is required to provide preliminary evidence, e.g., it is required to provide evidence showing that the respondent owns the alleged infringing product and the basic particulars of the alleged infringing equipment – such information as the specific location in the plant area where it is found, for example – so as to allow the court to formulate a suitable evidence preservation execution plan.
  4. It needs to be shown that the “party is unable to itself collect the evidence due to objective reasons”. A full explanation of the work done and attempts made by the applicant to collect evidence needs to be given to show that it has used all reasonable efforts and to demonstrate that the “party is unable to itself collect the evidence due to objective reasons”.
  5. Make advance preparations for a security deposit. Once evidence preservation is approved, it is necessary to provide security within a relatively short delay.

Based on the above-mentioned preparations, counsel should, in light of all laws, select the appropriate court in which to institute a legal action and actively liaise with the judge to convince him or her to assist in the evidence preservation and collection work.

The author has applied for evidence preservation in courts in numerous places, in a large number of patent infringement cases and, being thoroughly prepared, has succeeded in obtaining the support of many courts, laying a sound foundation for prevailing in the subsequent cases.

Chen Jian is a partner and an attorney-at-law at Sanyou Intellectual Property Agency and Beijing Wanrui Law Firm

Sanyou Intellectual Property Agency


国际企业大厦A座16层 邮编: 100033

16/F, Block A, Corporate Square

No.35 Jinrong Street, Beijing 100033, China

电话 Tel: +86 10 8809 1921 / 8809 1922

传真 Fax: +86 10 8809 1920

电子信箱 E-mail:



Copy link