Background Head and neck mucosal melanoma is a rare malignant disease with no clear and effective treatment to control the prognosis of patients. Aim To analyze the effects of different postoperative adjuvant treatments on the survival and prognosis of patients. Material and methods A retrospective analysis of 163 patients which were divided into five groups: no adjuvant therapy, postoperative radiotherapy, postoperative chemotherapy, postoperative chemotherapy and radiotherapy, and postoperative immunotherapy. Kaplan-Meier method and Cox regression analysis were used to analyze the prognosis in the different groups. Results Postoperative radiotherapy had statistically significant effects on local recurrence, distant metastasis, overall survival, progression-free survival (PFS) and recurrence-free survival (RFS); Postoperative chemotherapy and postoperative chemotherapy/radiotherapy had effects on distant metastasis, overall survival, PFS and RFS. However, postoperative immunotherapy did not show any significant effects. For patients with limited lesions who underwent endoscopic surgery, receive postoperative radiotherapy and postoperative chemotherapy/radiotherapy seem to have better prognosis. Conclusions and significance For the head and neck mucosal melanoma, different types adjuvant therapy can prolong the survival of patients to varying degrees compared with no postoperative treatment, but immunotherapy as a single adjuvant therapy does not show any advantages. We recommended that patients should receive radiotherapy and/or chemotherapy after surgery.