Objective: To investigate the predictive factors for the success of conservative treatment of isolated superior mesenteric artery dissections (ISMAD). Methods: The clinical data of 37 patients with ISMAD admitted from January 2012 to March 2017 were retrospectively analyzed. Of the patients, conservative treatment was successful in 18 cases, and failed in 19 patients. The relevant factors were compared between the two groups of patients to determine the predictive factors for the success of conservative treatment. Results: In patients having successful conservative treatment compared with those who had unsuccessful conservative treatment, the age and course of disease showed no statistical difference (both P>0.05), while the proportion of cases with superior mesenteric artery-distal aorta angle (SAA) less than or equal to 75° was significantly decreased (27.8% vs. 63.2%, P<0.05), the average distance of dissection was significantly prolonged (2.34 cm vs. 1.47 cm, P<0.01), the length of dissection was significantly shorter (3.13 cm vs. 4.57 cm, P<0.05), and the average degree of true lumen stenosis was significantly smaller (33.9% vs. 65.8%, P<0.01). Conclusion: SAA greater than 75°, relatively long distance of dissection, relatively short length of dissection and relatively small degree of true lumen stenosis are the predictors for success of conservative treatment of ISMAD. When conservative treatment is unsuccessful, safe and effective endovascular therapy can be selected.