In order to identify the hybrid purity of castor bean in early seedling stage or before sowing,castor bean hybrid verification and genetic diversity of F₁ seeds derived from CSR24×CSR181 hybridization were performed by SSR markers.It was showed that the results by different loci were basically consistent,and the hybrid rates estimated by most loci were from 13.46% to 17.27%,only which evaluated by RCM207 and RC129 were less than 10%.The variation was occurred on some loci of several individuals,4 progenies had nonparent markers and generated two new bands in primer RC242;the paternal special bands were absent and a new band was appeared in some progenies in primer Rco23,Rco26,Rco29,RC129,RCM613 and RCM999.The genetic diversity and cluster analysis of SSR data indicated that the distinct differentiation existed in F₁ progenies,the genetic variation was obvious,and genetic similarity coefficient between parents and progenies was 0.45~1.0.It was provided a method for early verification of true hybrids and offered the theoretical reference for genetic analysis of offsprings.