By using 7 inbred strains and 2 outbred NIH colonies of mice, the potency testing of Hepatitis B vaccine was performed. Significant differences were found between potency estimates derived from assays using different strains of mice. And it was likely that the variation of immune response to HB vaccine in mice was correlative with the H-2 haplotypes. Based on our experiments, a breeding selection has been made from the NIH colony for eliminating both non-q haplotype-bearing individuals and other poor res-ponders to HB vaccine.This new established colony is hopeful to become a standard stock for potency testing of HB vaccine in China.