This paper presents an RF pulse signal detecting system based on MSP430F1121, the pulse may be high-frequency, low-amplitude and narrow-width. A general design of the system is introduced. The system can effectively detect the pulse signal when pulse-widthτ≥ 0.7μs , duty-cycle D ＜ 1/2000, and its amplitude P ≥―15 dBm. By controlling the time between interruptions, the system can eliminate the influence of disturbance signal efficiency. Experiments have proved that the system is simple in its circuit, effective and reliable in operating performance.