Abstract: A 3-D radar target simulator is designed to provide an effective method for radar fault detection and online simulation training. This target simulator is based on DDS technology, using DSP + FPGA + DDS architecture, and a team of addition and difference simulation intermediate frequency echo signals are generated through software configuration, which can simulate radar target echo of specific azimuth, elevation and range. Using the target simulator in systematic joint test, the results show that the target simulator has the features of facile control, stable operation and flexible expansion.