104 serum samples from patients with liver diseases were detected for TTV DNA by nested-PCR method. The results showed that 25 of 104(24%) were positive for TTV DNA. Among 104 samples, 48%(12/42) were positive for nonA-E and G 19% (4/12) were positive for hepatitis A 25% (8/32) were positive hepatitis B 11.1% (1/9) was positive hepatitis C 4 of 6(66.7%) fulminant hepatitis cases were detected positive for TTV DNA. The partial gene of two TTV isolates from the patients were cloned and sequenced. The sequence analysis shows that there is 98.4% nucleotide identity between AB008394(from Japan) and one isolate from the patient (TTVEC023). The results suggest that TTV is associated with acute, chronic and fulminant hepatitis. TTV infection would be the important cause of non A-E and G hepatitis.