Objective Through MRI defecation films and digestive tract of transmission test, evaluate the diagnostic value of imaging for constipation, explore the causes of constipation. Methods In 58 cases with clinical diagnosis of constipation, MRI defecation film inspection, then make the digestive tract transmission test, imaging diagnosis reference Wang Yi and Gong Shuigen professor to measurement and diagnosis standard and compared with clinical or intraoperative results, were retrospectively analyzed. Results Among 41 cases with outlet obstruction, and 16 cases is rectal before protrusion, rectal mucosal prolapse in 5 cases, 7 cases before protrusion merger prolapse, 4 cases is pelvic floor spasm syndrome, perineum descending syndrome in 3 cases, multiple merger abnormal is 6 cases. Among 12 cases with abnormal gastrointestinal transmission, 8 cases is true slow transmission, 4 cases is pseudo slow transmission. Among them, 6 cases of outlet obstruction merge transmission anomalies. 37 cases is surgical treatment, 21 cases is drug treatment. Conclusion MRI defecation film unite digestive tract transmission test is a simple and noninvasive, comprehensive and dynamic inspection method for diagnosis of constipation cause, to help clinicians to formulate effective treatments.