Abstract: This thesis reported the result of fiber colonoscopy of 1430 cases, there are 106 cases was diagnosed as colon carcinoma by preoperation biopsy and pathological examine after operation, and they are staged advance (tumor with stricture type 58.5%, ulcerwith stricture type 41.5%), These tumor located at following sites, rectum: 62 cases(58.5%), sigmoid colon: 19 cases (17.79%), descending colon and flexura linealiscolon: 11 cases (10.4%), ascending colon and flexura hepatical colon: 13 cases (12.3%),and multifocal (ascending colon, sigmoid colon and rectum): 1 case (0.9%).Allcases regard the pathologic diagnose after operation as standard, 106 cases are treatedby operation, 92 cases (86.8%) performed radical operation or local excision, 14 casescan't be excised because there have widespread metastasis, and only receive palliativetreatment through fistulization or aorta intubate chemotherapy.This thesis discussedthe evaluation of fiber colonoscopy to diagnose colorectal carcinoma, the relation of carcinoma and adenoma.carcinoma and schistomiasis, indicated the clinical importance tofind the cancer of large intestine early.