Introduction: High-quality bowel preparation is an essential precondition for colonoscopy. Few studies have evaluated the smartphone WeChat application as a means of improving the quality of bowel preparation. Aim: To assess the effect of patient education by using smartphone WeChat application aids on the quality of bowel preparation. Material and methods: A multicenter prospective, endoscopist-blinded, randomized, controlled study was conducted. Patients were randomly assigned to three groups. A total of 478 patents in groups A were accepted for smartphone WeChat application, 477 in groups B were accepted for conventional education plus smartphone WeChat application while group C (473 patients) was a control group. The primary outcome was the quality of the bowel preparation according to the Boston Bowel Preparation Scale (BBPS). The secondary outcomes included polyp detection rate (PDR), cecal intubation rate, insertion and withdrawal time, anxiety score, self-rated sleep quality, and willingness to undergo another colonoscopy.