According to the 2024 Survey on Overseas IP Disputes Involving Chinese Enterprises released in May 2025 by the China Intellectual Property Society and the National Guidance Center for Handling Overseas IP Disputes, there were 870 U.S. patent litigation matters involving Chinese companies in 2024, including 587 new filings, a 31.03% year-over-year increase. Of those 587 new cases, Chinese companies were named as defendants in 312, and 136 cases involved Chinese parties on both sides.
As more Chinese companies enter the U.S. market, they inevitably encounter vigorous resistance from competitors in the United States or in other jurisdictions that hold U.S. patent rights. IP disputes arising from market competition are increasing, and patent infringement litigation—where technology and law intersect—has become a significant hurdle that many Chinese companies cannot ignore when doing business in the United States.
So, how should a Chinese company respond when sued for patent infringement in the U.S.?
Because U.S. federal district court procedures in patent cases differ in many respects from Chinese civil procedure—for example, discovery, Markman (claim construction) hearings, and extensive use of expert witnesses—Chinese companies should understand and leverage these features and proactively plan defense strategies across procedure, substantive defenses, and patent invalidation.
I. Make Full Use of U.S. Civil Procedure Rules
1. Service of Process
Unlike China, where courts serve the complaint and summons, in U.S. civil actions the plaintiff is responsible for serving the court-issued summons together with the complaint on the defendant.
For cross-border disputes against Chinese companies with no registered U.S. address, service must comply with the Hague Service Convention, i.e., through Chinese judicial authorities. This may take several months to over a year.
Accordingly, Chinese companies should avoid casually acknowledging or accepting U.S. court papers sent by email or regular mail, and should not agree to waive formal service. Properly using the gap between learning of a potential suit and formal service can buy valuable time to prepare a defense, and to search for and collect evidence for non-infringement defenses and counterclaims.
2. Venue and Jurisdiction
Some Chinese companies maintain U.S. subsidiaries or offices and may be better positioned to defend in the district where they are located, whereas patentees often file in forums perceived as favorable to plaintiffs.
As defendants, Chinese companies can invoke applicable provisions of 28 U.S.C. to transfer venue to a more favorable federal district court.
Example: Zhongshan Broad-Ocean Motor Co., Ltd. successfully transferred a patent case (No. 2:15-cv-443-JRG-GSP) from the Eastern District of Texas to the Eastern District of Missouri, a venue more advantageous to the defense.
II. Assert Comprehensive Substantive Defenses
1. Non-Infringement. Retain experienced U.S. patent counsel and expert witnesses to analyze whether the accused product or method omits one or more claim limitations. If any required technical feature is missing, the accused technology does not fall within the patent’s scope. Defendants can also leverage the Markman hearing to press the patentee toward narrow claim constructions, helping keep the accused product or method outside the asserted claim scope.
2. Prior Art / Prior Use. Search for prior art and, through discovery, request the patentee’s R&D records and background materials. Evidence that the defendant’s product or process predated the patent’s filing date supports defenses based on prior art and can lead to a finding of no infringement.
3. Unenforceability. U.S. law recognizes the doctrine under which a patent may be held unenforceable (e.g., due to inequitable conduct). Investigate whether, during prosecution before the USPTO, the patentee engaged in misconduct—such as intentionally withholding material prior art relevant to novelty or non-obviousness. If proven, the court may rule the asserted patent unenforceable, leaving it nominally valid but incapable of being enforced.
III. Challenge the Asserted Patent’s Validity
A plaintiff’s infringement case presupposes a valid U.S. patent. Defendants can attack that foundation by counterclaiming for invalidity in district court or by petitioning the USPTO to invalidate the patent—thus removing the patentee’s core leverage and potentially resolving the dispute at its root.
There are multiple USPTO pathways. Within one year of being served with a complaint, a defendant may file an Inter Partes Review (IPR). IPRs typically offer shorter timelines and lower costs compared with district-court invalidity litigation.
IV. Prepare Early to Mitigate Infringement Risk
Although there are many tools to defend U.S. patent suits, litigation in U.S. courts is costly and lengthy. If infringement is ultimately found, damages can be substantial, potentially disrupting a company’s overseas operations. The key, therefore, is prevention.
Before entering the U.S. market, Chinese companies should conduct freedom-to-operate (FTO) assessments to identify high-risk patents that their products might implicate. For any such patents, companies should formulate mitigation plans—design-around strategies, robust prior-art searches, and, where appropriate, preemptive invalidation.
Going further, for published patent applications filed by competitors in the U.S. market, companies can submit third-party observations to the USPTO to block or narrow risky claims before grant—removing legal obstacles at lower cost and smoothing the path for market entry.