A laser spot measuring system was designed to improve the position precision of a laser designator surveillance systems. All the components of the laser spot measuring system were introduced, respectively, and the relationship of all connected signals among these components was given. According to the laser backscattering in collecting laser spot images, a method was proposed to restrain the laser backscattering based on an asynchronous range-gating technology. To weakening the impact of atmospheric turbulence on laser spot imaging, an improved blind deconvolution algorithm was applied to the image process after the events for the laser spot image. Finally, the distortion of the spot image was adjusted and the spot position was computed by Gauss surface fitting method. The simulation experiments were designed and a practical field experiment was performed by the proposed system. The experimental results show that the precision of this laser spot measuring system is better than 0.3 pixel.