Abstract: In order to understand the characteristics of ambient noise in the bottom of the South China Sea, acoustic observations were made on the bottom of Middle South Shoal of the South China Sea from March 2021 to December 2021. The noise levels, kurtosis and skewness of noise in different frequency bands are statistically analyzed. The results show that there are seasonal differences in the ambient noise in the bottom of Middle South Shoal of the South China Sea. The overall performance is that the noise level in winter is higher than that in other seasons, while the difference between day and night is weak; there are many low-noise levels in the frequency band above 5 kHz, and the environment is quiet; the change trend of noise level over time in 8 kHz frequency band is consistent with that of wind speed over time; when the tropical cyclone passes through the sea, the noise level below 20 kHz in the sea area shows an overall increase trend, but different frequency noise levels are affected by the tropical cyclone to different degrees. The noise level in the 8 kHz frequency band is greatly affected by the change of wind speed, while the amplitude of the 200 Hz and 20 kHz frequency bands with the change of wind speed is relatively low.