Abstract: On December 18，2023，a M6.2 earthquake struck Jishishan Bonan，Dongxiang，and Salar Autonomous County，Gansu Province，China，with a maximum seismic intensity of VIII，causing severe environmental damage. This study aims to determine the basic parameters of the seismogenic fault and analyze its movement. To this end，this study，based on the two-pass differential interferometric synthetic aperture radar （D-InSAR） technique，obtained the coseismic deformation field of this earthquake using ascending and descending orbit from the Sentinel-1A satellite，as well as digital elevation model （DEM） data before and after the earthquake. Based on the dislocation theory in a homogeneous elastic half-space （the Okada dislocation model），a mapping model was established to link coseismic deformation and fault movement. The coseismic deformation field was used to fit the seismogenic fault，followed by the inversion for basic parameters of the seismogenic fault and the simulation of fault slip distribution. The results show that the maximum deformation from the ascending orbit data was about 6.65 cm，while that from the descending orbit data was about 7.12 cm. The seismogenic fault exhibited a strike of 308.14°，a dip angle of 61.57°，and a slip angle of 71.42°. Moreover，the fault presented a maximum slip of approximately 0.29 m located approximately 8 m below the surface and a moment magnitude of M_w6.17. The fault is characterized by thrust movement，with a minor left-lateral strike-slip movement. Based on the regional geological structure，the seismogenic fault is speculated to be the southern margin fault of Laji Mountain，with surface rupture caused by the earthquake.