Live attenuated Poliomyelitis vaccine (human diploid cell) is used for poliovirus prevention in children above 2 years old , Which was developed by Institute of Medical Biology , Chinese Academy of Medical Sciences , based on the other two products : Poliomyelitis Vaccine in Dragee Candy (Monkey Kidney Cell), Live ; and Poliomyelitis（Live）Vaccine (Monkey Kidney Cell),Oral . After its safety been proved in phase 1 clinical trail evaluation , the phase 2/3 trail was started in Guangxi Province, China during 2011-2012. The purpose of this trial is to assess the safety and immunogenicity in healthy children of 2,3 and 4 months old .