Abstract:Partial rbcL gene segments(1137bp) were sequenced in species from Saccharum and its related species, including one Arundinaceum and one Pennisetum purpureum sample. Sequence vqriation of rbcL gene in Saccharum and related species were found to be highly conservative, and identical sequences were presented between Saccharum and Miscanthus, and Narenga and Miscanthus, while sequences of some individuals from same genus had some variation. The results suggest that rbcL gene is not a good genetic marker for the phylogenetic study of Saccharum and related species.