Soil water is the main source of plant water consumption, and its change has an important effect on the whole ecosystem. Using GRACE satellite data and GLDAS-NoAH model, this study analyzed the spatial and temporal variation of soil water in the Loess Plateau from 2002 to 2020. Combined with the from 2002 to 2020 MODIS NDVI product data set of GEE platform and the precipitation data from 2000 to 2017, the correlation analysis of soil water changes was carried out for comparative analysis, and the M-K test method was used to test the change trend. The results showed that:(1) The monthly mean of equivalent water height (mm water column height) of GRACE from 2002 to 2020 was (-7.56±4.38) mm, and showing a significant decreasing trend from 2008. (2) From 2000 to 2020, soil water in the 0-10 cm soil layer showed no significant increase trend, while it showed no significant change trend in the 10-40, 40-100 and 100-200 cm soil layers, and it showed a significant decrease trend in the 200 cm soil layer from 2012 to 2020. (3) With the increasing of soil depth, the correlation between precipitation and soil water decreased significantly in the Loess Plateau from 2000 to 2017. Correlation coefficient decreased from 0.581 of 0-10 cm soil layer to 0.099 of 100-200 cm soil layer. The correlation coefficient between NDVI and soil water of the soil layer deeper than 200 cm 2002 to 2020 was -0.805, which was a significant negative correlation. The results revealed the change law of soil water in the Loess Plateau, revealed the correlation between precipitation and NDVI changes and soil water, which could provide a theoretical support for the next step of vegetation restoration in the Loess Plateau.