Spontaneous combustion of coal seam led to the physical and chemical properties change of mineral rock nearby, with complex electromagnetic field background. When collecting transient electromagnetic data, which was inevitably under the complex background of the electromagnetic field interference, the traditional de-noising method was unable to adapt to the complex electromagnetic background field exploration accuracy requirement. Application of Matlab software for computer simulation of wavelet de-noising, the simulation results showed that wavelet transform to remove the high frequency noise effect was good. The observed data of coal seam spontaneous combustion area processing results showed that selecting the appropriate wavelet cluster the wavelet analysis of coal seam spontaneous combustion area could get better de-noising effect.