Objective:To analyze the characteristics of the HBV rtA181 mutation,and to provide the theoretical basis for anti－viral treatment. Methods:Eighty－five patients’ serum samples of rtA181 mutation were collected,and the liver function,surface antigen,e antigen and HBV DNA at the occurrence of resistance were amalyzed. PCR products were sequenced to determine the resistance mutations and genotypes. Results:Eight different resistance patterns were observed in rtA181 mutations, which were mainly in adefovir(ADV) monotherapy and ADV plus or change LAM groups. There were 13(15.7%) patients with HBV genotype B and 72(84.3%) with genotype C. The genotypes showed no significant difference in rtA181 mutation patterns (P = 0.175). After occurrence rtA181 mutation,ALT,HBV DNA and HBsAg were still significant improved (P value were < 0.001,0.013 and < 0.001,respectively),and the HBsAg level was different between rtA181T and rtA181V group [(3.40 ± 0.35)lgCOI vs(3.62 ± 0.54)lgCOI,P = 0.030]. Conclusion:The rtA181 mutation was relevant to adefovir medication,and has no significant difference in HBV genotype B and C. Some patients still received biochemical and virological response after rtA181 mutation. HBsAg level of rtA181T mutation group was lower than that of rtA181V group.