The coseismic deformation field of 2021-05-21 Yangbi M_S6.4 earthquake in Yunnan Province was obtained by using Sentinel-1A satellite data and D-InSAR technology. The results showed that the coseismic deformation field of the Yangbi earthquake is distributed along the long axis near NW, and the signals of ascending and descending deformation are opposite. The maximum slip along line of sight is 0.1 m. Slips are mainly distributed in 2-12 km along strike and 1-9 km along down-dip direction, and the maximum displacement is 0.35 m. The seismic rupture is 9.8 km long and 4 km wide. The slip focus on the range of 3-6 km underground, and the slip angle is -146.7°. The coseismic deformation field and slip distribution model implied that the earthquake is a right-lateral strike-slip event, with rupture not reaching the surface. The inversion results of fault model showed that the moment magnitude of the mainshock is M_W6.1, and the seismogenic structure is a NW-trending right-lateral strike-slip fault. It is inferred that the seismogenic structure of the 2021 Yangbi M_W6.1 earthquake is a NW-trending blind secondary fault on the west side of Weixi-Qiaohou fault.