OBJECTIVE: To establish the phylogenetic trees based on internal transcribed spacer（ ITS） gene sequence

so as to quickly and accurately identify the origin of commercial slices of Astragali Radix. METHODS: The DNA of 14 samples of Astragalus membranaceus（ Fisch.） Bge.var.mongholicus（ Bge.） Hsiao and 8 samples of Astragalus membranaceus（ Fisch.） Bge. from different sources were extracted. ITS universal primers were designed and synthesized.After the amplification and sequencing

the phylogeny trees for all species were constructed by Neighbor-Joining（ NJ）tools with MEGA 6. 0 software. Totally 16 kinds of Astragali Radix pieces were collected from the market and then amplified by PCR with designed primers. The PCR products were directly sequenced and its species were differentiated and identified by constructing phylogenetic trees according to NJ method. RESULTS: ITS sequence had high homology for Astragalus membranaceus（ Fisch.） Bge.var.mongholicus（ Bge.） Hsiao and Astragalus membranaceus（ Fisch.） Bge..There were only a few mutation types in the whole ITS sequence region

such as G/A on base 128 and G/-/T/C on base 619

T/C on base 620

C/A on base 621

A/-/C on base 622

and C/A/-on base 623. With the help of the phylogenetic trees established by gene sequencing

the genetic and evolutionary relationship between Astragalus membranaceus（ Fisch.） Bge. and Astragalus membranaceus（ Fisch.） Bge. var. mongholicus（ Bge.） Hsiao in 22 samples can be distinguished

which can also provide the origin identification for 16 kinds of Astragali Radix in the market

including 12 for Astragalus membranaceus（ Fisch.） Bge. var. mongholicus（ Bge.） Hsiao and 4 for Astragalus membranaceus（ Fisch.）Bge.. CONCLUSIONS: The phylogenetic trees based on ITS sequence can be helpful for the original identification of Astragalus membranaceus（ Fisch.） Bge.var.mongholicus（ Bge.） Hsiao and Astragalus membranaceus（ Fisch.） Bge..