<p>Previous research has overlooked the dynamic shifts in public trust in the police. This study investigates the changing patterns of it in China from 2013 to 2023, a decade marked by the state-led legal reform known as Comprehensive Law-based Governance. Drawing on six waves of nationally representative data from the Chinese Social Survey (CSS), we employ the age-period-cohort-interaction (APC-I) model to disentangle age, period, and cohort effects. Results reveal three key findings. First, trust follows a U-shaped age trajectory, decreasing during early adulthood and rising later. Second, trust in the police has steadily increased since 2013, suggesting a positive period effect associated with ongoing legal reforms. Third, generational differences are striking: the Pre-Cultural Revolution Generation reports persistently high but stable confidence throughout the period; the Cultural Revolution and Social Reform Generations exhibit lower and declining trust; and the Law-based Governance Generation demonstrates the highest and increasing trust levels. These results emphasize how legal reforms may be leveraged to bolster institutional legitimacy and reshape public perceptions across generations. This study advances policing scholarship by incorporating temporal dimensions into the evaluation of public trust and provides broader insights into state-society relations in contemporary China.</p>