Phylogenetic relationships within the genus Rhododendron were studied using psbA-trnH intergenic spacer sequences. In the analysis, forty samples of thirty-six Rhododendron species, which belong to seven subgenus according to taxonomy system of Sleumer in "Flora of China" were analyzed. The results indicated that: all species are grouped into seven clades and all samples come from every same subgenus formed into a monophyletic clade with higher bootstrap value which supported the taxonomy system of Sleumer in "Flora of China". Pseudorhodorastrum as an independent subgenus was supported. The opinion of Chamberlian proposed the subg. Pseudazalea should be placed in subg. Rhododendron as a subsection Trichoclada was not supported by the reconstructed phylogenetic tree.