Abstract: Objective To investigate the prognostic factors of malignant melanoma. Methods The clinical and follow-up data were retrospectively analyzed in 382 patients with malignant melanoma admitted to the hospital from the January of 1985 to the December of 2004. A multivariate analysis was performed by the Cox proportional hazard model. The survival rate was determined by life table method. Prognostic index was calculated based on the Cox regression analysis. According to the prognostic index value, the patients were classified into high and low hazard groups; survival curve was drawn for the two groups of patients. Results As shown by the Cox regression analysis, the factors influencing the survival rate included tumor staging （RR = 1.56, P = 0.00）, patients′ sex （RR = 0.69, P = 0.01）, tumor site （RR = 1.06, P = 0.01）, tumor thickness（RR = 1.13, P = 0.04）, operation scope（RR = 0.72, P = 0.00）. The median survival period was 14.0 and 95.3 months in the low and high hazard groups, respectively; the difference between these two groups was statistically significant （P < 0.01）. Conclusions Tumor staging, thickness and site, patients′ sex, and operational scope are important prognostic factors. The prognostic index might be used to predict the prognosis of malignant melanoma.