Abstract: The effects of rain generated noise on underwater ambient noise spectrum during typhoon transit are analyzed by using numerical model and experimental data. This numerical model is based on the normal mode theory and the statistical analysis of rain generated noise. The ambient noise intensity without taking account of ship and wildlife noise is mainly the sum of rain and wind generated noise. The acoustic data collected in an experiment are used to investigate the characteristics of ambient noise. It is observed that the received noise intensity in deep water would be affected by the rainfall noise at the time of two hours before the eye wall of typhoon arrival and after its departure. Besides, the spectrum levels of rain generated noise are about 5-6 dB higher than those of wind generated noise at the frequencies from 1 kHz to 3 kHz, and the spectral slope of the former is flatter than the later one. By comparisons, it is shown that the simulated curves of the numerical model are in good agreement with the experimental data.