AIM: To establish the cell survival curve for primary hepatic carcinoma cells and to study the relationship between SF2 of primary hepatic carcinoma cells and radiosensitivity.METHODS: Hepatic carcinoma cells were cultured in vitro using 39 samples of hepatic carcinoma at stagesⅡ-Ⅳ. Twenty-nine samples were cultured successfully in the fifth generation cells. After these cells were radiated with different dosages, the cell survival ratio and SF2were calculated by clonogenic assay and SF2 model respectively. The relationship between SF2 and the clinical pathological feature was analyzed.RESULTS: Twenty-nine of thirty-nine samples were successfully cultured. After X-ray radiation of the fifth generation cells with 0, 2, 4, 6, 8 Gy, the cell survival rate was 41%, 36.5%, 31.0%, 26.8%, and 19%,respectively. There was a negative correlation between cell survival and irradiation dosage (r = -0.973, P＜0.05).SF2 ranged 0.28-0.78 and correlated with the clinical stage and pathological grade of hepatic carcinoma(P＜0.05). There was a positive correlation between SF2and D0.5 (r = 0.773, P＜0.05).CONCLUSION: SF2 correlates with the clinical stage and pathological grade of hepatic carcinoma and is a marker for predicting the radiosensitivity of hepatic carcinomas.