Abstract: The wave front phase aberrations can be corrected by deformable mirror in real time, which is the key element of adaptive optics system for reducing the effect of atmospheric turbulence. The wave front error can be compensated by deformable mirror with single actuator: one optical mode is generated with one actuator. Finite element analysis was employed to research the compensation capacity for the low order aberration of single actuator deformable mirror. The simulation results show that the wave front error of defocus, astigmatism and coma can be effectively corrected using single actuator deformable mirror by controlling the displacement of actuator. The peak valley (PV) values of fitting errors of defocus, astigmatism and coma are 1.5 m, 1.6 m and 1.2 m, respectively, comparing to the initial PV value of 5 m. The root-mean-square (RMS) values of fitting errors are 0.99 m, 0.63 m and 0.59 m,respectively.