In order to obtain the pure peristalsis pressure signal of the colon, a method for extracting the peristalsis pressure signal of the colon based on wavelet analysis was proposed in this paper. The colonic pressure signal was decomposed into five levels and the peristalsis pressure signal of the colon was reconstructed after detaching the interference signal. Besides, an experiment for eliminating abnormal data was conducted. The results showed that not only the abnormal colonic pressure signal was inhibited effectively, but also the detail characteristics of the colonic peristalsis pressure signals were maintained by using the proposed method. Compared with the peristaltic pressure signal containing interference signal, the extracted signal had higher signal noise ratio and lower mean square error.