Objective To evaluate 18F-FDG PET-CT imaging to the diagnosis of melanoma patients comprehensive follow-up after treatment and prognostic value. Methods A total of 40 cases of melanoma patients with comprehensive treatment, review of 18F-FDG PET-CT imaging and conventional imaging diagnosis, to statistical analysis using SPSS13.0 statistical software package, count data using four case table method to calculate positive predictive value, negative predictive value, sensitivity, specific, accurate, false positive rate and false negative rate. In combination with 18F-FDG PET-CT and histopathological corresponding qualitative diagnosis, with ROC curve to determine the optimal SUVmax melanoma lesions. Through the establishment of gender, age, focal SUVmax, treatment, lymph node metastasis, lesion COX proportional hazards regression model, analyze the influencing factors of overall survival. Results 40 cases of melanoma patients 18F-FDG PET-CT imaging in the diagnosis of the positive predictive value of 90% and negative predictive value of 100%, 86%, 96%, specific sensitivity, accuracy of 90%; Conventional imaging in the diagnosis of positive predictive value, negative predictive value of 79%, 72%, 73%, 65%, 65% sensitivity, specific, accurate %; Melanoma lesions best SUVmax is 2.5; COX proportional hazards regression model analysis showed that lesions SUVmax (relative risk, RR=1.312, P=0.009) and lymph node metastasis (RR=2.815, P=2.815) is the main factor that affect the overall survival rate. Conclusion 18F-FDG PET-CT imaging to the diagnosis of melanoma patients after comprehensive treatment than conventional imaging has high sensitivity, specific, accurate, important value to the evaluation of prognosis.