Cancer monitoring of Shanghai showed a rapid increase in the incidence of colorectal cancer. Colorectal cancer risk assessment allows for rapid screening of high-risk populations. The colorectal cancer screening of elderly residents is ongoing since 2013 in Shanghai. This initiative screened 85,525 people from 11 communities of the Qingpu District. Screening included a questionnaire-based risk assessment and two Fecal Occult Blood Tests (FOBTs). We conducted a retrospective case study of patients with positive screening results that underwent fibro-colonoscopy examinations to investigate their histories of schistosoma infection, smoking, alcohol consumption, and dietary habits. A total of 85,525 people were screened in this study. Colorectal cancer was resulted in a prevalence of 59.84/100,000. And the prevalence of schistosoma infection was 400/100,000. Among patients with schistosoma infection, the positive rate of FOBT was 67.01%, in contrast to an overall positive rate of FOBT among all subjects of 17.00% [(Pearson ⎥2=672.42, P < 0.0001, OR = 3.94 (3.67,4.23)]. The prevalence of colorectal cancer among patients with schistosoma japonicum infections was 4,155.84/100,000, while the prevalence of colorectal cancer among all subjects was 44.15/100,000 [Pearson2 = 980.62, P < 0.001, OR = 94.12 (53.05, 166.97)]. Our study found a high degree of correlation between late stage schistosoma infection of the intestinal tract and the occurrence of colorectal cancer and colonic adenoma. For patients with lesions caused by schistosoma infections of intestinal tract, the risk of colorectal cancer was higher than that of patients without intestinal schistosoma infections. Early screening and risk assessment can facilitate early diagnosis and treatment of colorectal cancer and colonic adenoma.