The collected field seismic data are accompanied by random noise interference, which needs to be eliminated by wavelet threshold denoising method. However, the soft and hard thresholding methods have some shortcomings in noise reduction. In this paper, a new threshold denoising algorithm is proposed to perform seismic data denoising. Firstly, a new threshold denoising method is designed based on the principle of soft and hard threshold method, and the relevant characteristics of the new algorithm are studied. Then, the wavelet base of the new threshold algorithm is defined as sym 3, and the denoising effect of the new method is evaluated by root mean square error (RMSE) and signal-to-noise ratio (SNR) through simulation experiments. Finally, the new threshold denoising method is applied to actual seismic data denoising. The results show that the improved threshold denoising method can remove random interference in seismic data, and the denoising effect is better than that of the old soft and hard threshold method.