ObjectiveTo evaluate variation of three key regions of HBV genome in patients with coinfection of hepatitis B virus (HBV) and human immunodeficiency virus type 1 (HIV1) as well as those only infected with HBV.MethodsForty serum specimens from patients with coinfection of HIV1/HBV(trial group) as well as 40 serum specimens from those only infected with HBV(control group) in Hunan Province were collected, the wholegenome of HBV was amplified and sequenced, the mutation sites were analyzed.ResultsHBV in serum of 59 cases were successfully genotyped and sequenced, 21 of which were from trial group and 38 from control group, there was significant difference in HBV load and genotype between trial group and control group (both P<0.05). In trial group, 4 patients were detected 22 amino acid mutations in the preS region of HBV in serum specimen, 12 were detected 45 nucleotide mutations in preC and basic core promoter (BCP) regions, the overall deletion mutation rates of amino acid in preS region of trial group and control group were 0.60% and 0.64% respectively, with no significant difference (χ2=0.042, P>0.05). There were no significant difference in mutations in key sites of preC and BCP regions between trial group and control group (both P>0.05), the overall variation rates in preC and BCP regions of trial group and control group were 1.36% and 1.73% respectively, difference was not significant (χ2=1.920, P>0.05).ConclusionHBV mutation in coinfected patients is basically the same as that in singleinfected patients, HIV1 has not obvious affect on the evolution of HBV mutation during a short time.