In attempt to learn the insertion patterns of hepatitis B virus spreading in northern China, we analyzed over 450 samples from chronically infected patients.Totally full length sequences of 79 HBV genomes were obtained.As well as the high rate of point mutation and deletions, 14 inserting sequences were found in 8 individuals (10.13%).Interestingly, except for two insertions at preS region where is the major deletion hot spot, most nucleotide additions were in core promoter.Further additional 109 fragments covering core promoter and core were then sequenced and insertions were detected in 23 samples (21.00%).