Healthy city (HC) construction, as an important path for many cities or regions at home and abroad to cope with economic, ecological and demographic problems, and to improve the image of cities, is gradually becoming an important grip for China to promote the construction of beautiful China, healthy China and ecological civilization. On the basis of systematically reviewing the connotation of healthy cities, this study constructed a HC assessment system, measured the HC construction performance of 284 cities in China using the combination model based on the analytic hierarchy process and entropy weight, and further applied the synthetic control method and interaction term model to quantitatively assess the implementation effects and impact mechanism of China's HC pilot policies. The results showed the following. (1) The average allocation level of HC construction performance in China from 2009 to 2019 showed an "N-shaped" fluctuating upward trend, rising from 0.3251 in 2009 to 0.3556 in 2019, an increase of 9.38%, but the average allocation level was between 0.3 and 0.4, which was still at a relatively low level. (2) The spatial distribution pattern of the HC construction performance showed the characteristics of "south > north" and "east > central", and mainly showed the spatial evolution pattern of gradually decreasing from the high value area with the Yangtze River Delta city cluster, cross-strait city cluster, Pearl River Delta city cluster, and Beijing-Tianjin-Hebei city cluster as the core. (3) The implementation of the HC pilot policy had a positive impact on the HC construction performance of most of the pilot cities, but there were differences in the policy effects. The driving effect on the HC construction performance of pilot cities such as Dalian, Wuxi and Yuxi was more significant, while the driving effect on the HC construction performance of pilot cities such as Baoji was not significant. (4) The HC pilot policy-related initiatives would have positive effects on HC construction performance through reducing pollution emissions and improving medical services, while the impact pathways of improving environmental quality and enhancing health culture atmosphere have not yet played a positive role. These findings could provide references for the implementation and improvement of the new round of HC policies.