Objective: To investigate the value of screening for early diagnosis of primary liver cancer (PLC)., Methods: A total of 18,816 persons, who were high-risk population of PLC, were divided randomly to allocated screening group and control group. In the screening group every individual was checked up by serum AFP test and ultrasound every 6 months but those in the control group were not., Results: Eighty-six patients with PLC were detected in the screening group, while 51 patients with PLC occurred in the control group. In patients from the screening group 60.5% were in the early stage, 45.3% of them were with small liver cancer. However, in the control group the figures were 0 and 0 respectively. In the screening group, 57 patients with PLC were detected by follow-up screening every 6 months, 77.2% patients of this series were in the early stage. However in the screening group the other 29 patients with PLC were detected by screening but they were not followed up every 6 months. Early-stage patients were only 27.6% in this series., Conclusion: This suggests mass screening, especially continual screening every 6 months in fixed population can diagnose PLC early.