Abstract: The mevalonate kinase (MVK) gene family of four plant species from Euphorbiaceae family i.e., castor bean (Ricinus communis), physic nut (Jatropha curcas), cassava (Manihot esculenta) and rubber tree (Hevea brasiliensis) was identified systematically based on the published genomewide and EST data, and the gene structure and the revolutionary relations of these species were analyzed consequently. The results showed that there were 2 MVK genes in all of the four plant species respectively, and all of the genes contained 4 introns. Homologous analyses revealed that MVK genes were widely distributed in different organisms including archaea, eubacteria and eukaryotes, suggesting an early origin of this gene family. Although a single copy of MVK gene was identified in most genome released species, gene amplification was found in these four Euphorbiaceae plant species similarly as in maize and poplar. The analyses on digital expression profiling suggested that in the leaf, flower, II/III stage endosperm, V/VI stage endosperm and seed organ tissues, the expression level of RcMVK1 was generally higher than that of RcMVK2. The highest expression of both the two genes was found in II/III stage endosperm, the lowest expression of RcMVK1 was in seed, whereas the lowest expression of RcMVK2 was in leaf tissue.