Administrative city is the specific implementation unit for the integration and optimization of nature reserves. It is of great practical significance to reveal the spatio-temporal evolution characteristics and development trend of city-scale nature reserves for the comprehensive construction of the nature reserves system with Chinese characteristics. Based on 10 observations of China's Nature Reserve Lists with a 5-year interval from 1975 to 2020, the standard deviation ellipse, exploratory spatial data analysis and spatial Markov Chain methods were first applied to characterize the spatio-temporal evolutions and developmental trends of Chinese nature reserves at the city-scale in this analysis, followed by the introduction of geo-informatic atlas analysis to construct the changing pattern of Chinese nature reserves. The results showed that: (1) The proportion of natural reserves increased obviously and tended to be stable at the city scale in China, but the low-value areas dominated overall. The proportion of nature reserves between cities was substantially different, and a spatial pattern characterized by"high in the west and low in the east" was gradually formed. The gravity center migration of the nature reserves showed a "southwest-northeast-northwest" spatial evolution pathway, with its moving distance and speed being gradually reduced. After 1990, the city-scale proportion of nature reserves had always shown a spatial distribution pattern of "northeast-southwest". (2)The city-scale proportion of natural reserves presented a significant spatial positive correlation and the overall correlation gradually increased, but the spatial aggregation level of nature reserves gradually decreased. The local spatial heterogeneity was strong, and the high-high and low-low aggregation areas were expanded. (3)The geo-informatic atlas analysis indicated that the city-scale proportion change of natural reserves followed the "early change-low frequency-step by step"mode, and the main change type was the vacant area changing into low value area. The transfer of the proportion of natural reserves types in the Chinese cities had stability and evident spatio-temporal heterogeneity, forming the "club convergence" phenomenon in the later stage (2005-2020), with the neighborhood background playing an important role in the transfer process. In the future, it is necessary to strengthen the assessment of natural resources in those vacant and low-value cities, to incorporate their most valuable areas into the nature reserve systems, and to popularize regional joint protection mechanisms to promote high-quality construction of the nature reserve systems.