Objective:To investigate the effect and the prognostic factors of radiofrequency ablation(RFA) for primary liver cancer(PLC).Methods :RFA was performed in 195 patients with PLC, and the efficency was evaluated with univariate analysis. Cox′s regression analysis model was used to analyze the factors affecting the prognosis.Results:In the whole group of patients, the 1, 2, 3 and 5year overall survival rate was 80.5%,67.4％,49.1% and 32.7% respectively,and in the patients with small PLC(the size≤3 cm),the 1, 2, 3 and 5year overall survival rate was 91.7%,81.2％,60.5% and 40.4% respectively. The Cox regression models indicated that the independent factors in determining the prognosis were: Liver function of ChildPugh stage, tumor size and occlusion of hepatic inflow during RFA.Conclusions:RFA is an effective miniinvasive treatment for patients with PLC, and especially for the patients with small PLC. The efficency of RFA for small PLC has the same outcome as that of surgical resection of the tumor. Liver function of ChildPugh stage, tumor size and occlusion of hepatic inflow during RFA are the independent prognostic factors.