Based on the comprehensive evaluation method, a comprehensive urban ecological carrying capacity (UECC) evaluation system is established. It includes ecological support, ecological resilience, and ecological pressure. Multiscale geographically weighted regression (MGWR) was used to conduct a thorough examination of the spatial and temporal patterns, and the factors that influenced the UECC of 286 prefecture-level cities in China from 2010 to 2019. The results show that (1) China’s UECC index ranges from 0.0233 to 0.2811 in 2019, which is still at a low level. (2) The spatial distribution is relatively stable: high-value agglomerations of UECC are distributed primarily in the Yangtze River Delta and Pearl River Delta, while low-value agglomerations are primarily distributed in the regions in the Central Plains. (3) All influencing factors have a positive effect on the improvement of UECC and are heterogeneous in spatial distribution. Lastly, this paper gives corresponding suggestions, so that governments can formulate differentiated policies and effectively improve UECC.