Abstract: It is introduced that based on the frequency of useful signal,electronic surge in the apparatus and electromagnetic wave disturb in coal mine,we divide them into the useful signal responded by geological body and interferential signal;make use of wavelet transfer to do multi-resolution analysis;pick-up useful signal and get rid of interferential signal by disassemble and reconstruct,then get a new signal.This method gets rid of the interferential signal successfully but does not lose useful signal.We can see the result from actual data:this method are resultful in wiping off the noises of transient electromagnetic signal.