The study analyzed healthcare utilization trends in China from January 2015 to April 2024 using interrupted time series analysis on outpatient visits and hospitalization data. The COVID-19 pandemic and the zero-covid policy caused a decrease of 1.21 billion (7%) outpatient visits and 140.9 million (13%) hospitalizations from expected levels from January 2020 to April 2024. The largest decreases occurred during the initial waves of the pandemic and strict zero-covid measures. A ten-point increase in the Policy Stringency Index prior to the cancellation of the Zero COVID policy led to a 7.2 percentage point drop in outpatient visits and a 6.2 percentage point drop in hospitalizations. After the end of the policy, utilization gradually recovered, but by April 2024 it remained below expected levels in 20 (65%) regions for outpatient visits and in 23 (74%) for hospitalizations. Regional differences showed the largest absolute reductions in developed areas such as Shanghai (4,997 fewer outpatient visits and 241 hospitalizations per 1,000 people) and the largest relative decreases in less developed regions such as Guizhou (16% of outpatient visits) and Shanxi (27% of hospitalizations).