To address the problem of the limited noise reduction capability of traditional seismic signal noise reduction methods, a noise reduction model based on RDBU-Net network is proposed. The model uses Residual Dense Block (RDB) to replace the ordinary convolutional layer in the U-Net network to enhance the feature extraction ability and reduce the problem of feature loss. Furthermore, noise in the same frequency band is removed, the signal-to-noise ratio (SNR) of the seismic signal is improved. Using the Stanford global seismic dataset to train, verify, and test the RDBU-Net model, the experimental results show that the average SNR and average correlation coefficient of the seismic signal after noise reduction using the RDBU-Net model are significantly improved. Compared with the traditional seismic signal noise reduction method and other deep networks, this noise reduction effect is excellent. Further tests are conducted on an actual noisy seismic dataset drawn from Jiuzhaigou, Wenchuan, in China. The results show that the RDBU-Net model still has good generalization for unknown samples.