Objective To establish the base of molecular system-theory on medicinal plants of Angelica L.and to offer molecular gists for finding the efficacy difference of them.Methods The PCR technique was utilized together with the clone technique to get the ITS gene and measure its genic sequence.Statistical analyzing and branch analyzing were carried out by Phylip software and genetic distance difference in every kinds can be calculated with MEGA3.Results ITS1-5.8 S-ITS2,belongs to one of medicinal plants of Angelica L.,its sequence length extents 600 to 629 bp.Subtracting 5.8 S,its length is 165 bp,the length of ITS is 468 bp.The medicinal plants of Angelica L.are divided into two groups by dendrogram.The genetic distance of A.sinensis from Gansu Province is obviously different from the other medicinal plants of Angelica L.,but the distance difference compared with Levisicum officinale is smaller.Conclusion It suggests that the above result be identical to the efficacy of medicinal plants of Angelica L.It may be an important reason of explaining why the efficacy between A.sinensis and other medicinal plants of Angelica L.is so different.