Patents play a key role in enterprise competition. With the emergence of the “Patent Great Wall” , patent litigation has become more and more frequent. Infringed companies take the initiative to initiate patent litigation to defend their rights while transmitting signals of their operations quality to stakeholders. However, no study has yet focused on feedback from enterprise customer groups. This study collected operational and legal data of Chinese listed companies from 2007 to 2020 to explore the signaling effect of enterprises' patent litigation behaviors and their influence mechanism on customer stability. The result revealed that enterprises' proactive patent litigation can effectively enhance customer stability. In addition, signal consistency positively affects the signaling effect, while the intensity of market competition has a negative moderating effect. This study enriches the related research on signaling theory from the perspective of the legal signaling effect. It supplements the analysis of the influencing factors of customer stability and provides a new perspective for the study of enterprises' patent litigation motivation. It also gives some advice on business practices.