The existing literature ignores patent invalidation as a means of administrative innovation protection. Through the patent invalidation event to identify the initial invalidation party and the patent owner, this paper uses the event study method to explore the market reaction of investors to patent invalidation. Empirical evidence based on listed companies from 2014 to 2020 shows that: (1) firms who initiated patent invalidation have a significantly positive market reaction, while the firms that owned this patent have a significantly adverse market reaction. (2) Those effects increase with the quality of the patent, indicating that the patent quality strengthens the market reaction to patent invalidation. (3) Those effects are more pronounced in firms with more patents, higher competition, and high-tech industry, proving that industry patent race strategy, situation, and intensity affect the market reaction. This study enriches the literature on the patent race and market reaction and can be used as a reference for strengthening the regulation of the patent race.