Abstract: To explore a new method of identifying Paris polyphylla var. yunnanensis, the genomic DNA from P.polyphylla was extracted and the chloroplast psbA-trnH sequence was amplified by PCR.After spliced by CodonCode Aligne,the intraspecific and interspecific genetic distance (K2P) and neighbor-joining (NJ) tree were built by MEGA5.0 software.The result showed that the chloroplast psbA-trnH  fragments found in intraspecific variation was small and the average K2P genetic distance was 0.007,while interspecific was 0.025.The maximum interspecific genetic distance of P.polyphylla was significantly less than the minimum K2P of intraspecific.The DNA barcoding comparison and NJ tree showed that psbA-trnH sequences can be used to distinguish P.polyphylla. The method was stable,accurate and will provide new technical means for clinical medication safety.

Key words: Paris polyphylla var. yunnanensis, DNA barcoding, psbA-trnH, molecular identification