Abstract: Objective 　To evaluate the therapeutic effect s of 3-dimensional conformal radiationtherapy for small hepatocellular carcinoma and analyze the prognostic factors. Methods 　Forty-one cases of small hepatocellular carcinoma were t reated with three-dimensional conformal radiotherphy, The Kaplan-Meier was used to evaluate the survival rates, and the COX regression model was used to analysis single and multi-factors of the prognosis. Results 　The overall 1-, 2-, 3-year survival rate were 95. 1 %、90. 2 %、80. 5 % respectively. Mean survival time was 49. 5 months, Media survival time was 56 months. The side effects of radiotherapy could be tolerated. Multi-factors analysis revealed that the number and the diameter of tumor were independent prognostic factors affecting the patient s'survival ( P < 0. 05) . Conclusion 　The results suggest that three-dimensional conformal radiotherapy for Stage Ⅰ hepatocellular carcinoma is a relatively safe and effective method. The number and the diameter of tumor were independent prognostic factors affecting the patient s'survival.