Abstract: Objecttive To analyze the clinical phenotypes of a familial adenomatous polyposis (FAP) pedigree, to determine the interval between follow-up colonoscopies of dominant FAP patients and to discuss the safety and clinical signifi cance of multiple colonic polyps resection. Methods After identifying the proband of FAP, we performed colonoscopies in adult members of the family. For patients diagnosed as dominant FAP, we carried out treatment under colonoscopy and follow-up. Results There are 25 people in this family, with 11 males and 14 females. Only three members, two females and one male, were diagnosed as conventional dominant FAP. Besides, this male is the son of one of the two females. Tracing back to the pedigree, 3 females were FAP and died of colorectal cancer. From October 2007 to May 2012, we had performed 27 times of treatments under colonoscopy and follow-up for the three dominant FAP. Two polyps（2.5 cm，3.0 cm, respectively）were treated through polyp stripping and trepanned resection, and the other 1 799 polyps all underwent high-frequency electrocautery, excision and cauterization with hot biopsy forceps, and so on. After the high-risk polyps were treated, the interval of colonoscopy follow-up was once every 6 months. The operation process was safe. During the follow-up, we have found high-risk adenoma with the scales shaped mucosa, but no cancerous adenoma. Conclusion Multiple colonic polyps resection through colonoscopy still has high safety, and this treatment has great clinical signifi cance for patients who do not accept colon surgery. We preliminarily determined that the interval of colonoscopy follow-up was 6 months in terms of prevention, but this needs to be further evaluated, including adding drug prevention measures at the same time.