Prior Use of a Patent in China: What Production Records Need to Prove

By Pan Jianxing · Published 30 October 2026

A Chinese manufacturer responding to a patent complaint may say that it was making the product before the patent was filed. For an overseas rights holder, that statement deserves a structured evidence review. For a business relying on the defence, a general account of long trading history is insufficient. The relevant issue is whether qualifying earlier activity supports the particular continued manufacture or use now in dispute.

Identify the defence and its date

Article 75(2) of the Patent Law addresses manufacture of the same product, use of the same method, or necessary preparations before the patent application date, followed by continued manufacture or use within the original scope. Confirm the legally relevant date, including any applicable priority under Article 12 of the Implementing Regulations, before sorting the evidence.

This differs from a prior-art defence. Prior art concerns public availability of a technical disclosure; prior use examines the defendant’s qualifying earlier activity and its limits. Confidential internal records may be relevant to prior use without establishing a public disclosure. Success on this defence should not be described as cancellation of the patent.

Match the earlier technology to the accused activity

Start with the product or process version alleged to infringe. Identify its relevant technical features and compare them with the earlier drawings, process instructions, samples or production files. A shared model name is not enough when the mechanism, material arrangement or process steps changed over time.

Build a version history that explains revisions, approval dates and implementation dates. Retain original digital files and their surrounding records, including release approvals and supplier correspondence where lawfully available. A recently exported drawing displaying an earlier date needs support for when that version existed and when it was used. A later employee statement can explain records, but should not replace records that should exist.

Test whether preparations were sufficiently concrete

Article 15 of the Supreme People’s Court’s patent infringement interpretation identifies alternative qualifying forms of necessary preparation: completion of the principal technical drawings or process documents needed to implement the invention; or manufacture or purchase of the principal equipment or raw materials needed for implementation. The historical text refers to former Article 69(2); the corresponding current statutory provision is Article 75(2).

Connect each purchase to the relevant implementation. A generic machine invoice may establish acquisition of equipment but leave unanswered whether it was the principal equipment needed for this product or process. Pair it with specifications, acceptance records, commissioning documents and the technical plan. A proposal to explore manufacturing is different from completed necessary preparations.

In a hypothetical tooling purchase, the purchase order, mould drawings, supplier delivery record and acceptance report can collectively show what was prepared and when. If one item relates to a different product revision, identify that difference openly instead of merging the files into a single chronology.

Establish lawful origin and the correct entity

The same Article 15 rejects a defence based on unlawfully acquired technology or design. Review how the technical information was obtained: internal development, an authorised transfer or another documented lawful route. A dated file does not answer a credible allegation that the information was taken from someone else without authority.

Identify which legal entity performed the earlier acts and which entity now manufactures or uses the technology. Group membership, a shared factory address or a common director does not by itself explain the chain. Keep any corporate succession or business-transfer documents alongside the technical evidence, rather than assuming that every affiliate can invoke the original activity.

Measure the original production scope

Article 15 includes the pre-application production scale and the scale achievable using the existing equipment or production preparations. The inquiry therefore needs both output records and evidence of the capacity supported by those earlier resources. Do not equate the protected scope automatically with either a single historical shipment or all later factory capacity.

Separate original machinery, production lines and preparations from later additions. Document technical capacity, operating assumptions and the source of each figure. A retrospective capacity calculation should disclose its inputs and limitations. Commercial ambition or a plan to expand is not a substitute for evidence of qualifying existing capacity.

Check transfers and licences separately

The interpretation does not generally allow post-application transfer or licensing of the previously used technology to justify another party’s activity as continued use within the original scope. It recognises an exception where the technology or design is transferred or inherited together with the original enterprise. Examine the actual transaction and continuity; do not treat a stand-alone licence as automatically carrying the defence.

A review file should therefore contain the relevant date, technical comparison, development or acquisition evidence, preparation records, original capacity analysis and entity history. Missing links should be listed explicitly. A rights holder can then challenge specific gaps, while a defendant can assess whether the evidence supports the defence actually asserted.

Contact Pan Jianxing with the patent number, the disputed product or process and a non-confidential outline of the earlier activity. Sensitive technical records should be shared only after the conflict check and secure document arrangements.

Pan Jianxing
China-qualified lawyer · Partner, 北京市长安律师事务所
Beijing & Shenzhen
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