Plague is a potentially fatal infection in humans caused by the bacterium Yersinia pestis. Pneumonic plague is typically diagnosed in humans with high mortality. It has a long history for plague as an agent of biowarfare, and poses a serious threat to international security. Althought the killed whole-cell plague vaccine and live attenuated vaccine have been licensed, they are rarely used today because of toxicities, limited evidence for efficacy to prevent plague, and limited commercial availability. In the last twenty years,the recombinant subunit vaccines comprised by fraction 1 capsule(F1)and virulence-associated (V)antigens as the main composition have caused widely attention with providing greater protection than vaccines comprised of either subunit alone. This study was aimed to explor the safety and immunogenicity of a new type plague subunit vaccine which comprised natural F1 antigen and recombined V antigen (F1+rV).