An experimental impulse radar system is presented. This system，known as free space system，is located in a microwave anechoic chamber. The transmitting and receiving antennas，A/D converter，controlling board and data processor are specially designed. This system can receive echoes of many kinds of targets and obtain the results in real time. In this paper，we also discussed the data processing technique and present a regularization means to solve the impulse response，estimate AR model parameter and give the real data processing results. All these results verify the efficiency of this system. In the last，we introduce the procedure of measuring the echo signal of RAM-covered target. Through the comparison，we verify that impulse radars have the ability of anti-stealth targets.