To improve the performance of wireless laser communication (WLC) systems, wavefront sensorless adaptive optics based on deformable mirror (DM) eigenmodes was used to correct the distorted far-field spot. A set of DM eigenmodes conforming to the derivative–orthogonal relationship is derived, and the system simulation model under different atmospheric turbulence intensities is established by combining Fresnel diffraction and multiphase screen transmission principle. The influence of mode bias on the correction effect is analyzed. The ability of the proposed method to correct the distorted far-field spot was studied by using Strehl ratio (SR) as the evaluation index. The influence of the proposed method on the coupling efficiency of single-mode fiber and bit error rate performance of the WLC system is discussed. Indoor and outdoor experimental systems were built. The indoor experiment results show that the proposed method can increase the SR of the system from 0.11, 0.32, and 0.56 to 0.57, 0.71, and 0.88, respectively. The outdoor experiment results show that the proposed method can effectively correct the wavefront distortion caused by dynamic atmospheric turbulence.