Objective:To obtain the anthrax protective antigen in E. coli,prepare its monoclonal antibodies,and analyze the function. Methods:The gene coding for anthrax protective antigen PA10 was synthesized and cloned into pUC57 plasmids. After being identified by enzyme analysis,the target gene was inserted into pColdⅡ plasmid. By sequencing confirmation,the plasmid pCold II-PA10 was transformed into E. coli BL 21(DE3) and induced by IPTG and low temperature for expression,and identified by SDS-PAGE. The recombinant protein was purified by affinity chromatography and identified by Western blotting. After the mice BALB/c were immunized by the recombinant protein of PA10 as antigen,the monoclonal antibodies were prepared. Results:The recombinant protein of PA10 was used to immunize mouse,and obtain 4 strains of specific monoclonal antibodies(respectively named as 2G8, 5A8, 7B3,9C9). The protection of anthrax toxin test in vitro,proved that one of four monoclonal antibody strains(7B3) has a comparatively large activity to neutralize anthrax toxin with protection rate up to 96%. Conclusion:This research successfully constructed the anthrax Protective antigen PA10 in E. coli and prepared its monoclonal antibodies,which laid the foundation for further development of chimeric neutralizing antibodies used to treat anthrax.