After over 60 years of construction, China's nature reserves have played a vital role in maintaining national ecological security, protecting biodiversity, preserving natural heritage, and improving the ecological and environmental quality. This paper has systematically sorted out the existing spatial distribution data of 2672 nature reserves in China (excluding Hong Kong, Macao, and Taiwan), formed a relatively complete geo-spatial database. Preliminary analysis was conducted on statistical characteristics from the aspects of development process, protection type, construction scale, etc. And the methods of geographical concentration index and kernel density index were used to analyze the spatial distribution characteristics of nature reserves from different dimensions, such as sea and land distribution, provincial distribution, temporal and spatial distribution, agglomeration distribution and so on. The results showed that: (1) China's nature reserves were rich in number and type, roughly experienced five development stages of starting, slow development, steady development, rapid development, and stable and perfect stage. The main types of nature reserves were small and medium-sized forest ecosystem, wildlife, inland wetland and aquatic ecosystem. (2) They were spatially clustered with significantly provincial differences, showing the characteristics of less in the west and more in the east, and clustering in the west and scattering in the east along the Hu Huanyong Line. (3) There were obvious differences in the cluster trend among different types and management levels of nature reserves, forming 11 significant aggregation areas, such as Huangshan-Huaiyu Mountain, Northeast Guangdong Hills, Nanling, and Wuyi Mountain. (4) The construction scale and continuous aggregation effect of nature reserves decreased from west to east, which were closely related to the changing trend of the "three-step ladder" terrain structure in China. Finally, this paper discussed the main reasons for spatial pattern of existing nature reserves in China, including objective natural conditions and subjective human factors, and summarized the existing problems in the spatial distribution and development of nature reserves, and put forward some suggestions for establishing the network of nature reserves with perfect distribution and the integration of land and sea, scientifically defining the types of protected areas, gradually optimizing the boundaries of nature reserves, and enhancing scientific research and monitoring effectiveness. In the comprehensive and deepening reform stage of China's protected area system, which will shift from nature reserves to national parks as the main body. This study makes up for the limitations and timeliness of the existing research results, it is expected to provide some scientific reference for the spatial distribution optimization and development of nature reserves.