Objective To find out clinical characteristics and natural history of post transfusion HCV infection. Methods 83 subjects who have received the blood from a same blood donor from January 1998 to July 2002 were investigated by the method combining cross-sectional study with retrospective study. HC V-antibody, HCV RNA, liver function, abdomen B-ultrasound and Fibroscan were detected. Results The HCV-antibody were all positive. The HCV RNA of 56 out of the 83 cases were positive. The chronicity rates of hepatis C were 76.3% (29/38) in male patients and 60.00% (27/45) in female patients respectively, without significant difference (x2 = 2.99, P = 0.11). The average age of the HCV RNA positive patients was (36.54 ± 14.37) years old. The average age of the HCV RNA negative patients was (27.43 ± 12.51) years old. A significant difference (T = -2.41, P = 0.018) existed between. The HCV genotype was typelb. Among the HCV RNA positive patients, 10 cases were with mild asthenia, anorexia and abdominal distention, 9 cases with increased serum ALT, 12 cases.with chronic hepatitis and 1 case was diagnosed with decompensated liver cirrhosis. Conclusion The clinical manifestations of HCV infection are occult and chronic. The chronicity rate is related to gender and the age when infection was caught.