Phylogenetic relationship and fatty acid components of 21 cultivars (hybrids) and 1 wild Yongzhou variety of Ricinus communis were investigated. The results showed that: ①twenty RAPD primers were picked out from 296 10-mer primers for RAPD analysis; and 73 bands were obtained by use of the 20 primers, among the bands, 42 had polymorphism, accounting for 57.7%; the result of cluster analysis by use of UPGMA method showed that 21 genotypes could be classified together with genetic distant value of 0.1468. ②The castor oil contained mainly ricinoleic acid, oleic acid and linoleic acid, the contents of which were 72.82%～89.54%, 2.97%～8.54%, 3.47%～10.55%, respectively; there was little palmitinic acid, stearinic acid and linolenic acid in castor oil; the respective content of the palmitinic acid and stearinic acid was about 1%, and the content of the linolenic acid was around 0.5%. The content of ricinoleic acid among different cultivars of Ricinus communis showed big differences.