On November 25, 2016, an M_W6.6 earthquake occurred in Aketao region, Xinjiang. Based on the Sentinel-1 data, the line-of-sight co-seismic deformation field of the earthquake was obtained, and the Bayesian method was used to invert a single fault with a strike of 106.9°, a dip of 73.8°, and a focal depth of 17.35 km. On the basis of a geometric model of the fault, the slip distribution was inverted by the steepest descent method (SDM). The results showed that there are two slip peaks on the fault plane. The maximum slip on the west side of the fault is 0.66 m, with a depth of 11.7 km; the maximum slip on the east of the fault is 0.83 m, with a depth of 7.5 km. According to the inversion results, the LOS deformation was simulated, and the maximum residual error is ~5 cm. A double-fault geometric model with dip angles of 70.79° and 55.33° was constructed to invert the slip distribution. The results showed that the slip distributions of the single-fault model and the double-fault model are consistent, but the maximum slip value is different. Relative to the slip distribution of the single-fault model, the slip of the double-fault model increases on the west side, with a value of 0.68 m; while it decreases on the east side, with a value of 0.77 m; the maximum residual error is reduced by ~2 cm. The area of the Coulomb stress increase in the double-fault model matches the distribution of aftershocks.