Abstract: In recent years, global climate change and human activities have become increasingly severe. Studying the influencing factors of the dynamic changes of terrestrial water storage can help to deeply understand the temporal and spatial distribution of terrestrial water storage, and provide a basis for regional water resources management and protection. Based on（Gravity Recovery and Climate Experiment） GRACE data and eight climatic factors, this paper uses the trend analysis, cross-correlation analysis and（Partial least squares regression） PLSR model to analyze the（Terrestrial Water Storage Anomaly,TWSA） variation trends and the influencing factors in the South area of China（Yunnan, Guizhou, Sichuan, Guangxi, Hunan, Hubei and Chongqing） from the grid scale（1o×1o）.The results show that, from 2002 to 2017, the TWSA in most study area, except the western region, exhibited a significant growth trend. The highest increase rate reaches 0.9cm/year in the junction area of four provinces（Chongqin, Guizhou, Hunan and Hubei） where the dominant pattern of TWSA variation in this region is guided by the long-term and seasonal trends. In Yunnan, central and southern Sichuan, southern Guangxi, and the eastern of Hunan and Hubei provinces, the dominant pattern of TWSA changes over time is seasonal variation. At the monthly scale, the TWSA dynamic is closest to the air specific humidity. 85% of the grid TWSA changes can be explained by climate fluctuations. The central and northern parts of the study area are significantly affected by the regulation of large reservoirs. In other areas, the influence of reservoirs on the annualscale changes of TWSA in this area is not significant. At the annual scale, the change of TWSA in the whole region is still mainly affected by climatic factors. More than 60% of the change in terrestrial water storage can be explained by climate change, and rainfall is the main controlling factor for the annual change of TWSA in more than 70% of the study area. Only the vicinity of the Three Gorges Reservoir TWSA is still affected by a combination of anthropogenic activities and climate change.