bjective To separate the SO-Rb50 cells antigen corresponding to the monoclonal antibody of anti-retinoblastoma. Methods The antigen corresponding to the monoclonal antibody of anti-retinoblastoma was separated elementarily by ion-exchange chromatography, and was identified by dot-blotting using the monoclonal antibody of anti-retinoblastoma. The target protein band of the antigen was separated in light of sodium dodecyl sulfate-polyacrylamide gelelectrophoresis. Results A special unmixed band of SO-Rb50 cells antigen was separated with the relative molecular weight of 83×103.Conclusion The antigen corresponding to the monoclonal antibody of anti-retinoblastoma could be separated from SO-Rb50cells.(Chin J Ocul Fundus Dis，2003，19：152-155)