The summer precipitation in China is mainly affected by the East Asian summer monsoon, and the main factor affecting the monsoon is the land-sea thermal contrast. Based on the ECMWF / ERA5 reanalysis data and CN05.1 gridded precipitation data set from 1979 to 2022, this paper defines the European-Atlantic land-sea thermal contrast and two types of East Asian-Pacific land-sea thermal contrast: East Asia-North Pacific and East Asia-Subtropical High land-sea thermal contrast. The characteristics of three land-sea thermal contrast and the spatial and temporal characteristics of summer precipitation in China are studied, and the effects of land-sea thermal contrast on the mean and variability of summer precipitation in China and the influence of variability on extreme precipitation are analyzed. The results show that: (1) The precipitation in Northeast China, the lower reaches of the Yangtze River and the Tibet Plateau is significantly affected by the land-sea thermal contrast. The mean and variability of summer precipitation in these areas are increasing, and the increase of variability increases the probability of extreme precipitation in these areas. (2) The land-sea thermal contrast between East Asia-Pacific and Europe-Atlantic has maintained an increasing trend over the past 40 years and has shown an increasing trend under the medium emission scenario, and the land surface warming is higher than that of the ocean. (3) The main contribution of precipitation generation and change in Northeast China is the land-sea thermal contrast between East Asia-Pacific and East Asia-Subtropical High. The main contribution to the precipitation in the lower reaches of the Yangtze River is the land-sea thermal contrast between East Asia and the Pacific. The main impact on precipitation in the plateau area is the thermal contrast between East Asia-subtropical high and Europe-Atlantic sea and land. Finally, the results of LBM simulation further confirm that the Euro-Atlantic thermal contrast increases the precipitation in the western plateau and decreases the precipitation in the eastern plateau. These findings provide an important basis for us to understand the temporal and spatial variation of summer precipitation in China and the physical mechanism behind it.