The terrestrial water storage changes (TWSC) in Tianshan Mountains, Xinjiang of China was inferred using the GRACE monthly gravity data from 2003 to 2013. The noise existed in GRACE data was filtered by the combination of de-correlated technique and 300km Gaussian filter, and the GRACE post-process errors was reduced by the scaling factor, and the effect caused by GIA was cut down by the model provided by Paulson. The final GRACE result is consistent with the GLDAS and CPC hydrological models. The preliminary result indicates that the water storage present a decreasing rate which is about -0.54±0.27 mm/a in the Tianshan region, However, the TWSC fluctuates largely, specially, it shows a significant decrease in October 2008, which coincides with the drought conditions in the same period. The spatial distribution of TWSC shows a downward trend in the most parts of Tianshan region, with the maximum rate of -5.6±1.6 mm/a appearing in the middle of the Tianshan Mountains.