Four kinds of isoflavones, i. e. tectoridin, tectorigenin, iridin and irigenin used as contrastive standards to carry on the qualitative analysis and content determination of isoflav ones of 16 species of rhizomatous medicinal plants from Iridaceae were present. The content of irigenin in Belamcanda chinensis was the highest , which reached 1. 36% ; tectorigenin the highest in Iris tectorum , 1.50% ; in Iris dichotoma , irigenin the highest, 0. 46% ; contents of irid in and irigenin in Iris blodowii were 0. 58% and 1. 14% respectiv ely; irigenin in I . leptophylla was 0. 81% . Besides, I. confusa had consider able contents of 4 kinds o f isoflavones.