Abstract: In order to obtain the time domain electromagnetic response of radar target excited by UWB electromagnetic pulse, this paper proposes a method of time domain echo simulation based on forward modeling of scattering center. Starting from the target geometric model, we use the spatial ray diversity technique to separate the strong scattering sources, and construct the target attribute scattering center model by using the model parameter forward determination method to characterize the target high-frequency electromagnetic scattering characteristics, and then the simulation operation is performed under the ultra-wideband(UWB) pulse excitation to obtain the target time domain echo signal. Taking a typical target SLICY as an example, based on the scattering center model of forward modeling, the radar echo signals under different UWB electromagnetic pulse excitation are quickly obtained, which is in good agreement with the one-dimensional distance image obtained by high-frequency simulation method. The validity of the echo simulation method proposed in this paper is verified, which provides a new idea for the research on the fast electromagnetic response of targets excited by different radiation sources.