To solve the problem of feature extraction and target understanding in underwater image due to blurry underwater image and low contrast between target and background during underwater target detection, an underwater target detection algorithm based on frequency domain attention is presented. Firstly, the method transforms the training set image into the frequency domain, and uses the low frequency feature guiding suite (LFGS) to calculate the frequency component. Then the component will be applied as a parameter to the low frequency feature extraction model (LFM) to better extract the low frequency features of the image. The features that fuse the low frequency information of the image are further extracted to generate the high-level features. Finally, the high-level features are input into the detection head for detection. The average accuracy is 83.35% on URPC2021 dataset, which verifies the validity of this method.