Abstract: Acoustic method is the main method to detect gas leakage under water surface. It is difficult to extract and analyze the bubble acoustic signals when the leakage flow is small, because the ambient noise is strong and its frequency band overlaps with bubble sound. To solve this problem, an algorithm combining frequency domain accumulation and time-frequency detection is proposed in this paper. After increasing the signal-to-noise ratio by frequency domain accumulation, an adaptive time-frequency detection algorithm is used to extract and analyze periodic bubble acoustic signals. Experiments on the sea show that the method in this paper can effectively detect continuous leaking bubbles under strong environmental noise.