This work introduces the wavelet filter technique based on the soft threshold algorithm. The proposed method is applicable to the noise suppression during the detection process of the laser electromagnetic acoustic transducer (EMAT) technique. Experiments have been carried out on the 6016 aluminum plate, and the ultrasonic signal of surface defect has been processed by wavelet filter designed by Matlab. The results show that the technique has good prospects in the engineering applications of laser-EMAT testing.