Generally speaking, the spectrum of feeble signal folds the spectrum of sea clutter, and the location discrepancy between the target and its surroundings is small. So it is difficult for the classical processing in the frequency domain or space domain to detect the feeble signal in the ocean. This paper presents a new approach with Wigner-Ville distribution based on the linear frequency modulation signal detection in the ocean whereas WVD has the time-frequency local characteristic for LFM signal. It studies the difference between the new approach and the classical frequency approach for signal detection using the real data of the sea clutter collected by the radar in the condition of the several signal-clutter-ratios. The results show that the new approach has evident advantages compared with the classical approach. When the signal-clutter-ration is -14.3dB, it still detects the target effectively.