Abstract: Based on the traditional time domain shooting and bouncing rays (TDSBR), the scattering field of the target is calculated by the time domain physical optics (TDPO) algorithm based on analytic integral. Compared with the traditional SBR, this new method obviously reduces the number of ray tubes and saves computer memory. It is an efficient method for analyzing the scattering problem of electrically large objects. The numerical results demonstrate the reliability and efficiency of the method.