Abstract:In order to reveal the chloroplast gene and adaptive evolution characters of Rhodophyta, the 17 rbcL genes of Compsopogon and the similar group of freshwater red algae were selected, the bioinformatics of proteins encoded by rbcL genes of Compsopogon were analyzed by using software PAML4.9, and the selection sites of genes were detected by using branch model, site model and branch-site models. The results showed that the secondary structure of protein encoded by rbcL of Compsopogon was mainly composed of α helix and β folding, so its structure was very stable. The phylogenetic tree with the maximum likelihood method showed that the inner group had only one species, could be divided into three small branches, and they had obvious geographical distribution. No significant positively selected sites were detected under all three evolutionary models, indicating that most of the sites were under negative selection pressure. Therefore, there is no adaptive evolution of rbcL gene in Compsopogon.