The information of the underwater acoustic field is obtained from the water surface by the laser coherent detection method. The frequency of the underwater vibration is extracted from the interference signal by the interference between the reflected light and the reference light on the water surface. The vibration features of the underwater acoustic field in the signal can be effectively enhanced by the method of spectrum analysis and fast Fourier transform (FFT) filter feature extraction method. Laser coherent detection gets the information from the water surface in real time under the condition that the vibration source is located underwater 35 cm, respectively with 1 000 Hz, 2 000 Hz and 3 200 Hz vibration. Through experimental data analysis, the results show that the laser coherent detection can effectively obtain the vibration information of underwater acoustic field, and FFT filter method can effectively enhance the features of the target.