Abstract: Coding sequences（CDS）of five house-keeping genes i.e. Ubiquitin（UBI），Cyclophilin（CYP），Actin，Glucose-6-phosphate 1-dehydrogenase（G6PD）and Beta-tubulin（TUB）were obtained by Reverse Transcription Polymerase Chain Reaction（RT-PCR）from 7 wild and 1 cultivated tree peonies. Sequence comparative analysis demonstrated that nucleotide sequences of five genes were relatively conservative and the similarity of nucleotide sequences was about 99.04% to 99.69%. Furthermore，5 phylogenetic trees were constructed by using nucleotide sequences of these house-keeping genes from the 8 tree peonies. The phylogenetic tree analysis results showed that the 8 tree peonies could be clearly divided into two groups，viz. subsect. Vagiantae and Delavayanae. While each phylogenetic relationship of wild species in different sect. had a few differences，because of the degree of conservatism from 5 kinds of house-keeping genes. Considering to the five phylogenetic trees，it was found that Paeonia ostii and P. suffruticosa always cluster together. And these results indicated that there was close relationship between P. ostii and P. suffruticosa and it was deduced that P. ostii may take part in the origin of tree peony cultivars. In addition，P. rockii and P. decomposita was always clustered together，and it was demonstrated that the relationship between P. rockii and P. decomposita was very close；P. lutea and P. delavayi was always clustered together，and it was demonstrated that their relationship was also close. P. potaninii divergence time is earlier than P. lutea and P. delavayi. According to previous phylogenetic relationships of P. potaninii，P. lutea and P. delavayi，we recommend P. potaninii as a separate species.

Key words: tree peony, house-keeping gene, phylogeny, evolution