The adsorption and release of rHBsAg extracted from the final dosage form on various ion exchange resins and under different pH conditions were investigated after its peptide map and isoelectric point (PI) determination. Efficient antigen adsorption to the anion exchange resins occurred when the pH value of the protein buffer was adjusted to 5.0. In purification of rHBsAg derived from the yeast crude extract using Q Sepharose FF column, with adjusting the pH value of the crude extract to 5.0 (i.e., near to the target protein PI) and using 2M NaCl, rHBsAg with high purity (up to >95%) was obtained.