Accurate measurement of laser spot parameters after transmission in the atmosphere is a key technical means for studying the effects of laser atmospheric propagation and analyzing the performance of laser emission systems. The methods of measuring laser far-field parameters mainly include array detection method and camera imaging method. However, the current measurement and analysis of laser atmospheric transmission effect basically use array detection method. Because the detector array target detectors cannot be arranged uniformly and tightly due to the limitations of space physics and R&D costs, this will cause the distortion of the sampling spot and the far-field spot parameters cannot be accurately measured. Aiming at this problem, a set of laser parameter measurement system based on diffuse reflection imaging method is designed in combination with the high resolution of the camera. The minimum measurement resolution of the system is less than 0.39 mm, and the average deviation of the centroid position is 0.05mm, the uncertainty of the power from the measurement spot to the target is better than 10%. The system can effectively measure the tracking accuracy and target power of the laser emission system, and has accumulated a certain theoretical basis and experimental data for analyzing the laser atmospheric transmission effect and analyzing the performance of the laser emission system.