For the special problems on underwater laser detection,a special data acquisition system is designed.AD603,a variable-gain amplifier,is used in the pre-amplifier circuit for restraining the back scattering and amplifying the laser signal of target.The data acquisition and data buffering based on ADC08200 and FPGA make the circuit structure simple and scalable.The data transmitting and system control are based on the C8051F MCU.This system is stable when working and has been applied in some underwater laser detection system.