Abstract:【Objective】 To analyze the colonoscopy results of 3 600 case health examination, to investigate the incidence of occult colorectal diseases. 【Methods】 A retrospective analysis of 3600 cases of colonoscopy, pathological type, observe and record the subject's location, the subjects were divided into young group (<60 years old) and the elderly group (over 60 years), the difference between the two groups of subjects in proportion. The subjects were divided into symptomatic group and asymptomatic group two. The difference between the proportion of lesions between the two groups. Analysis of sex ratio, age distribution, colonic polyps living areas (urban and rural) difference. 【Results】 The subjects of colonic mucosal lesions in 734 cases, among them, the youth group accounted for 15.49%, the elderly group had a proportion of 32.81%, the incidence of elderly group was significantly higher than the proportion of the young group, and the difference was statistically significant (P < 0.01); the proportion of male elderly group was significantly higher than that in young group, the difference was statistically significant (P < 0.01); there was no significant difference of lesions in two groups (P > 0.05). 765 cases of symptomatic group subjects, asymptomatic group of 2 835 cases, the symptomatic group of pathological changes in the proportion of 29.67% is significantly higher than that in asymptomatic group the proportion of 17.88%, and the difference was statistically significant (P < 0.05); symptomatic group colon melanosis ratio, proportion of colorectal cancer, colorectal chronic inflammation were significant than those without symptoms, and the difference was statistically significant (P < 0.05). The incidence rate of colon polyps (20.34%) incidence rate of female is significantly higher than the elderly (9.88%), the incidence rate (22.89%) higher than the young group. The incidence of significant (12.94%), the city's incidence rate (17.24%) was significantly higher than the incidence rate in rural areas (9.38%), and the differences were statistically significant (P < 0.05). 【Conclusion】 There is a high incidence of colorectal disease in healthy people, colonoscopy is an effective method for screening colorectal lesions.