RAPD markers are used to study the genetic diversity of the main planting on 37 castor varieties widely cultivated in china according to the oil content and other characteristic of different castor varieties. Genetic distance of 37 Chinese castor varieties is studied by RAPD markers analysis. RAPD analysis shows that a total of 122 bands are amplified from random primers of 20 S series, including 71 polymorphic bands with polymorphic rate of 58.20%. 37 castor beans are divided into four major groups in the phylogenetic tree. One castor germplasm is included in1, 2, 3 groups respectively, and two sub-groups are included in the 4 major group.