Based on the multi-source datasets, including GLDAS and GIMMS NDVI3g during the period of 1981 to 2015, the spatiotemporal pattern of terrestrial water storage (TWS) and its components in Tibetan Plateau were investigated with Theil-Sen Median slope estimator and Mann-Kendall trend test, and the influence mechanism of hydrological cycle process on the changing trend of TWS was identified using the water balance method, correlation analysis, and Hurst index method. The results showed that the precipitation and melting of glacier snow increased, and TWS increased at a rate of 0.7 mm per year due to climate change during the period of 1981 to 2015; TWS of Tibetan Plateau increased significantly in northern parts, while decreased in southern parts; in most areas of Tibetan Plateau, TWS mainly consisted of soil moisture at the depth of 0 to 200 cm, and the soil moisture of different layers had significant spatial heterogeneity; precipitation in northern and eastern Tibetan Plateau was mainly lost through evapotranspiration, and the runoff coefficient in southern parts was larger than that in other regions.