Objective:To analyze the clinicopathological features, diagnosis, and treatment of anorectal malignant melanoma (ARMM), and to explore its prognostic factors and misdiagnosis. Methods:A total of 36 patients with ARMM were enrolled in this study from January 2000 to November 2016 in Nanfang Hospital, Zhujiang Hospital, and Guangdong Provincial Hospital of Traditional Chinese Medicine. Results: The clinical manifestations of ARMM were not specific. The odds of misdiagnosis were as high as 52.8% in this study. The 1-and 3-year survival rates were 75%and 35%, respectively, with median survival time of 24.51 months. Survival rate was correlated with tumor size, invasion depth, clinical stage, and lymph node metastasis (P<0.05), but was not related to patient age and gender. The median survival time of the three groups of patients (surgery alone, surgery-based combination therapy, untreated) were 39.21, 26, and 15 months. The difference was not statistically significant. No difference in survival was found between patients under-going abdominoperineal resection and wide local excision. Conclusion:ARMM has poor prognosis and is easily misdiagnosed as a ma-lignant tumor. The prognostic factors are tumor size, invasion depth, clinical stage, and lymph node metastasis. Surgical treatment can extend survival. To avoid misdiagnosis and prolong survival, early diagnosis and early treatment are recommended.