Objective To study the application value of Au-Pt alloy porcelain fused to metal(PFM)of full metal margin to posterior teeth. Methods 99 patients with Au-Pt alloy PFM restoration were recruited. 182 posterior teeth were restored. 93 posterior teeth were restored with Au-Pt alloy PFM of full metal margin, 89 posterior teeth were restored with Au-Pt alloy PFM of concave shoulder. After 1 and 3 years, the clinical effect in marginal adaptation /gigival health /secondary caries /the color of the gingiva and the stability were observed. The clinical effect in marginal adaptation/gigival health and secondary caries of posterior teeth of Au-Pt alloy PFM of full metal margin had not obvious change, but they were to the adverse direction about Au-Pt alloy PFM of concave shoulder (P<0.05). Results One year later, the clinical effect on marginal adaptation /gigival health /secondary caries and the color of the gingival had no significant difference between the two groups. Three years later, The good proportion of marginal adaptation of Au-Pt alloy PFM of full metal margin(92.47%) was better than Au-Pt alloy PFM of concave shoulder(82.02%). The proportion of periodontal lesions and secondary caries of the former (18.28% and 3.22%)were better than the latter(34.83% and 11.24%). The degree of the former gum being shaded was worse than the latter, the differences was statistically significant (P<0.05). Conclusions In the long run, posterior teeth restored with Au-Pt alloy PFM of full metal has good margin marginal adaptation / lower gum disease rate and secondary caries rate, but gum has greater risk of dyeing. Posterior teeth of Au-Pt alloy PFM of full metal margin can be recommended as clinical routine design.