Abstract: Objective To evaluate the efficacy of the simultaneous immunization of anthrax vaccine and leptospira vaccine with animal experiment for the further use in large population.Methods Ninety-six mice were randomly divided into 6 groups and the number of male and female was equal.The mice were injected subcutaneously with different doses of the two vaccines.A combination of 1/10,1/20,and 1/40 dose of live attenuated anthrax vaccine and 1/5 and 1/3 dose of leptospira vaccine were administered to 5 groups and 1 group was employed as blank control.Blood samples were collected from tail vein every week for detecting the specific anti-protective antigen(PA) IgG and antibody of spore by indirect enzyme-linked immunosorbent assay(ELISA) and the specific agglutinating antibody of leptospira vaccine by darkfield microscope agglutination test(MAT).Results IgG was induced in the mice inoculated with the live attenuated anthrax vaccine.The titers of anti-PA and anti-spore were 1:504 and 1:513,respectively.There was a significant difference in antibody titers between different groups.The average titers of gtippotyphosa and autumnalis were 1:231 and 1:610.There was no significant difference in specific agglutinating antibody of leptospira vaccine.Conclusion The optimal doses of simultaneous immunization of live attenuated anthrax vaccine and leptospira vaccine are 1/10 and 1/5 of human doses.