Based on the GPS data in 1991 ～ 2004 and the least-squares collocation method，we analyze the crustal deformation in Chinese mainland． The results show that the first-order crustal deformation is unchanged in different periods in Chinese mainland． It reflects the background of regional tectonic activity． The strain rate is much higher in the Western China，especially in the Qinghai-Tibetan Plateau and Sichuan-Yunnan area． The variations in different periods are affected by seismicity in the same time． The GPS data after 2004 show the post-seismic deformation of 2001 Kunlun Mountains M8． 1 earthquake．