Abstract: In order to investigate the relationships between hepatitis B virus (HBV) genotype and HBV core promoter mutants. Serum samples from 69 infected patients were determined for HBV genotype by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods and for HBV basic core promoter (BCP) gene mutants by PCR-microplate nucleotide acid hybridization-ELISA methods. By PCR-RFLP, HBV from 69 patients with hepatitis B can be divided into three type, i.e. type B, C and D. Viral genotype C was identified in 41 cases, genotype B in 18 and genotype D in 10 case, the percentages of type B type C and type D were 69.4%, 26.1%, 14.4% respectively. Twenty-three of 69 HBV infected patients were found to have mutants in HBV BCP region at nucleotide 1762/1764, among which 18 cases were detected with genotype C, 3 cases with genotype B, and in 2 cases with genotype D. The mutation in BCP region at nucleotide 1762/1764 was significantly more frequent in genotype C than B patients (43.9% vs. 16.7%, P<0.05) , but HBV BCP gene mutants was not found to have significant different between genotype D and genotype C or genotype B (P>0.05) . The results show genotype of Lanzhou mainly consists of type C and type B, genotype D are rare. There were a clear link between HBV genotype and HBV BCP gene mutations at nucleotide 1762/1764, HBV BCP mutations may be a new reason that genotype C have severe hepatitis HBV BCP mutations may be a new reason that genotype C have severe hepatitis disease.