This study proposes a method for 3D deformation monitoring of surface targets. Firstly, the radial deformation information is obtained by radar, and the 2D deformation information in the vertical plane of radar line of sight is obtained by optical equipment. Then, based on multi-source image matching, the information fusion of radar deformation monitoring data and optical deformation monitoring data is realized. Finally, the deformation of the fused data is solved to obtain the 3D deformation of the target. The experimental results show that when there is a certain angle between the actual deformation direction of the target and the radial direction of the radar, the relative error of the deformation monitored by this method is obviously small, which can be reduced to less than 1/3 of the traditional radar monitoring error.