Urban growth and contraction are the inevitable result of rapid urbanization. Excessive growth or contraction will bring problems such as resource mismatch and ecological environment deterioration. Based on the nighttime light data of China's districts and counties from 1992 to 2019, this paper deeply explores the temporal and spatial dynamic characteristics and causes of urban growth and contraction in China. In order to provide reference for the future new urbanization construction, balanced allocation of resources and national development policy-making. The results show that: ① Urban growth and contraction alternate in China, and the polarization between growth and contraction is more and more obvious. ② The center of urban growth has been moving in Nanyang city. The growth structure is mainly zonal and supplemented by a dot. The belt growth structure includes the coastal urban belt and the recently formed "Beijing―Zhengzhou―Nanchang" urban belt. Point structure refers to the agglomeration growth phenomenon with inland provincial capital cities as the core. ③ The center of contraction shifted from Xingtai City to Ankang City, and the center of contraction changed obviously. The contraction structure gradually changed from scattered point contraction to "Beijing―Xi'an―Chengdu―Kunming" belted contraction structure. ④ Global financial change cycle, industrial structure transformation, national policies and other factors are the main causes of urban growth and contraction in China.