The surface acoustic wave(SAW) immunosensor is a new kind of biosensor. A high-frequency detection system for SAW immune sensor is designed in this work. The system uses the phase-locked loop(PLL) to control the output signal frequency and the input signal frequency tracking lock. By measuring the frequency change, the system can complete the detection of the acoustic surface wave immunosensor, and the results are displayed on the LCD screen. The test results show that the detection system can accurately measure the sensing signal within the frequency range of 156~162 MHz, and the maximum measurement error of the system is only 0.85%, which meets the actual engineering needs and can be widely used in the high-frequency detection field of surface acoustic wave immunosensor.