Abstract: A measurement system based on scanning diffuse reflection imaging was developed for space-time distribution of laser intensity. The measurement system mainly consisted of spoke-shaped sampling structure, synchronous signal generator and CCD imaging system. Instead of the traditional static diffuse reflecting screen, sampling was realized with several spoke-shape dynamic rotating arms, which was feasible for online measurement of laser intensity distribution. Besides high resolution of the traditional method, there were more advantages in this scanning diffuse reflection imaging method, e.g.high laser attenuation ratio, strong power against laser destruction, simple structure and better maneuverability. Comparative experiments with the diffuse reflecting screen imaging method demonstrate high correspondency between the two methods. This system can be applied in the real-time monitor of laser intensity distribution in laser irradiation effect experiments.