The invention discloses an electrocardiographic 
signal de-noising method based on adaptive threshold 
wavelet transform. The method is characterized by comprising following steps: step 1: using the Mallat 
algorithm, the 
wavelet function sym6 and the number of 
decomposition layers J are selected, and the noisy 
ECG signal is decomposed by 
wavelet to obtain approximate coefficients and detail coefficients; step 2: setting the threshold for adaptive detail coefficients at each layer and selecting the 
threshold function; step 3: performing adaptive threshold 
processing on the detail coefficients ofeach layer, removing 
power frequency interference and myoelectric interference, and removing 
baseline drift by 
processing the approximation coefficients; step 4: performing 
wavelet reconstruction on the electrocardiographic signals after 
processing to obtain approximate optimal estimate value of signals. The method of the present invention makes full use of the multiresolution feature of the 
wavelet transform. An adaptive threshold 
selection method is provided. Different thresholds are used at each level to separate the 
noise and 
signal flexibly, improving the separability of 
signal characteristics; in the three aspects of visual, 
mean square error, and signal-to-
noise ratio, the effect is better than the traditional method, and the detailed information of the image is retained better, which has higher practical value.