Present the comprehensive protection algorithm combining Fourier transform, wavelet transform and wavelet entropy theory for the accuracy of the protection algorithm used by the underground coal mine protector, Resolve the sampled signal into stationary and nonstationary signals using the wavelet multiresolution analysis characteristic, and process stationary signals using Fourier transform and dealing with nonstationary signals using wavelet entropy. Establish the model of underground power supply and distribution system, and simulate the improved protection algorithm. The result shows that the comprehensive protection algorithm combining Fourier transform, wavelet transform, wavelet entropy theory reflects the operating status of underground power lines more comprehensively, and it has good theoretical value to achieve reliable operation of underground coal mine protector.