The InSAR coseismic motion is used in the inversion analysis to determine Nam Ma fault parameters. The Single-patch model yields a coseismic slip of 2.5 m. From the Multi-patch model, the maximum slip in top patch is 1.95 meters at depth of about 1 kilometers. When compare with the values obtained from field survey, we found rather large differences in western segment while the surface slip are almost the same in kilometres 14-16.