Abstract: A semi-physical simulation system of Xi’an Pulsed Reactor is developed for the purpose of providing the analog signal source, verifying the power regulation method and personnel training for the digital instrument and control system of Xi’an pulse reactor under construction. The design philosophy of semi-physical simulation system is proposed and the system frame is presented. The core physical simulation model is improved and the real-time core simulation program is coded by MATLAB. The human-machine interface is programmed by the software Kingview, and the rod control and rod position measurement are carried out by programmable controller S7-200. A series of hardware equipments, including the control rod driving mechanism simulator, the signal generator and the manual operation board, are developed. And the internal communication of the system is established. The change of the core power when the control rod is raised or lowered, and the pulse parameters after the pulsed rod is emitted are simulated with the semi-physical simulation system. The results are in good agreement with the experimental data on the reactor. The output of the signal generator is measured and the consequence is in accordance with the expectation. It is shown that the semi-physical simulation system can realize the design purpose and has good performance.