Abstract: AimTo identify “Shegan” ［Belamcanda chinensis (L.) DC.］ and relative medicinal plants of Iris including Iris tectorum Maxim., I.dichotoma Pall., I.germanica L. and I.japonica Thunb. by ribulose 1,5-bisphosphate carboxylase Large Gene (rbcL) sequence analysis. MethodsGeneral DNA was isolated from the fresh leaves of Belamcanda chinensis and 4 Iris spp. by CTAB. A pair of primers was designed to amplify the rbcL gene and PCR Preps DNA kit was used to purify the PCR products. The rbcL sequences were determined by ABI (Applied Biosystems Inco.) Prism 310 Genetic Analyzer. ResultsA fragment of about 750 bp of rbcL gene from Belamcanda chinensis and 4 Iris spp. were amplified and sequenced. The rbcL sequences of Iris tectorum, I.dichotomaPall. and I.japonica were reported for the first time. The rbcL sequences of 5 species of Iridaceae were aligned and analyzed using Clustal (Version 8.0) and MEGA (Version 2.0.) programs. The nucleotide number of difference is from 1.000 to 20.000. The tranversions is from 0.000 to 9.000 and the transitions is from 0.000 to 14.000. Phylogenetic tree based on rbcL partial sequence data indicated that the eleven samples of 5 species clustered separately. Conclusion The sequence variation of rbcL can be used to identify Belamcanda chinensis and 4 species of relative medicinal plants of Iris. The molecular phylogenetic tree accords with the classical taxonomy.