The gene fragment encoding ATR(CMG2)-EXCELL (excellular potion of anthrax toxin receptor/capillary morphogenesis factor) was cloned into a secretory expression plasmid and then expressed in media supernant of Pichia pastoris. The recombinant rATR(CMG2)-EXCELL expressed was about 20% of the total proteins in media supernant. About 1 mg electrophoresis purity rATR(CMG2)-EXCELL could be obtained after the purification of 1 L culure using chelating column. In vitro binding activity analysis and cell protection experiments have shown that rATR(CMG2)-EXCELL has an excellent biological activity. The successful expression of rATR(CMG2)-EXCELL has placed a solid foundation for the research on binding mechanism of ATR and PA(protective antigen) and developing new cure for anthrax.