Because the negative pressure caused by oil pipeline leak wave propagation to the monitoring point of leak point of the upstream and downstream, may make the point pressure signal to produce a larger shocking, with the shock curve it will produce some noise.Contrary to this phenomenon, getting pressure signal collected by pipeline monitoring sites ，combining wavelet transform and median filtering method , the denoising simulation experiments carried out under in the MATLAB software surrounding, came to the conclusion that the method can remove the interference in negative pressure wave signal well.