Seismic fault parameters can be inversed with Okada model based on deformation data before and after earthquakes in focal region and its adjacent area. Co-seismic displacements can be simulated by using these parameters,and then regional velocity field obtained by deducting the co-seismic displacements from the observed displacements by GPS method. We processed and analyzed the data in the northeastern edge region of the Qinghai-Tibet plateau observed during 2001-2003 in two steps:firstly,the displacements generated by Kunlun Ms8. 1 earthquake of 2001 in this region was simulated,and secondly,deducted the co-seismic displacements from it and obtained the horizontal crustal velocity field. The results reveal:1)the effect of Kunlun Ms8. 1 earthquake on crustal deformation in this region is significant;2)the velocity field obtained with this method is better than the original GPS velocity field in reflecting the status of regional crustal movement and strain.