The invention discloses an optical fiber early warning system noise reduction method and device based on wavelet analysis. The method and device are applied to an optical fiber early warning system of an oil pipeline. The method comprises the steps of reading source files used for recording sample signals, converting the binary source files into multiple sets of wave files, inputting the sets of wave files to a wavelet analysis noise reduction subprogram and obtaining target signals after noise reduction is carried out on the sample signals in the sets of wave files through the wavelet analysis noise reduction subprogram, and outputting the target signals. By means of the method and device, the accuracy and the effectiveness of warning information provided by the optical early warning system are guaranteed.