Abstract: The design and realization of a pulse Doppler radar signal simulator is presented. The simulator's parameters are set in Windows interface. With a ADSP21062 PCI card in the host computer, the simulated digital radar signals are produced. At the same time, the PCI card receives the radar DSP processed results, then adjusts the radar system parameters according to the processed results. The simulator's theory and the key problems including choice of reference frame, producing of clutters and target echo are introduced, The results show that it is easy to change the simulator's parameters, so the simulator efficiently verifies the processing arithmetic.