Firstly, using data of GPS horizontal velocity field in China Mainland from 2009 to 2011, aided by inver- sion of negative dislocation, we found locked segments with energy accumulation at main fractures in Xinjiang, the northeastern margin of Qinghai-Tibet Block, Sichuan-Yunnan and the North China. Secondly, we studied the accumulation rate and locked depth and difference at different regions or segments of main fractures and their possible relationship with preparation of strong earthquakes. The result indicated that: ( 1 ) Strain-accumulating rate was the highest in Xinjiang area, average locked depth was about 20. 9 km; Strain-accumulating rate in Si- chuan-Yunnan area was the second, average locked depth was about 16.3 km; There existed strain accumulation to some degree in northeastern margin of Qinghai-Xizang Block, average locked depth was about 15.7 km, and the strain accumulation rate in North China was the lowest, average locked depth was 16. 0 km. (2) At pres- ent, there exited relatively higher energy accumulation in west of Southem Tianshan, the eastern of the bounda- ry between Sichuan and Yunnan, from the middle segment of Honghe Fault to the western Yunnan, the westem segment of Qilianshan Fault, the segment of the northern margin fault of West Qinling Mountain near boundary between Gansu and Qinghai, the boundary among Shanxi, Hebei and Inner Mongolia Autonomous.