Aiming at the necessity of torpedo laser proximity fuze detecting underwater near field target, study on Monte Carlo simulation of underwater laser fuze echo was carried out. The Monte Carlo simulation model of underwater target echo was developed based on the characteristics of underwater laser fuze detection. In order to improve the echo simulation accuracy of the underwater non-Lambertian target, The probability distribution of photon reflecting direction based on bidirectional reflectance function was derived. Then the direction of photon reflection was randomly sampled according to the probability distribution. The underwater target echo under the condition of different distances and the incident angle was simulated. The results show that target echo amplitude decreases rapidly with the increase of target distance and incident angle. The dynamic range of signal peak achieves 11.5 dB when target distance changes within 6~12 m; the dynamic range of signal peak achieves 9.2 dB when target distance is 8 m and incident angle changes within 0~45°. The experiment of underwater target laser detection was conducted in a water tank to verify the correctness of the simulation method. The experimental data have a good consistency with the simulation results. It improves the effectiveness of traditional Monte Carlo method in non-Lambertian underwater target echo simulation which provides a theoretical reference for underwater laser fuze design.