Abstract: Through the inhibitory effects of leaching solution from Viburnum seeds on seed germination of Brassica rapa chinensis, the study analyzed the distribution and soluble chemical characteristics of endogenous inhibitor existing in Viburnum seeds. In this way, scientific basis could be provided for breaking dormancy of Viburnum plant seed. The experimental results showed that the inhibitory effects of leaching solution from 4 kinds of Viburnum seeds with different solvents such as water or methanol were significant on seed germination and radicle growth of Brassica rapa chinensis. The sequence of activity of water-soluble inhibitor in seed coat was: Viburnum mongolicum＞V. koreanum＞V. burejaeticum＞V. sargenti. The sequence of activity of water-soluble inhibitor in endosperm was: V. mongolicum＞V. sargenti＞V. burejaeticum＞V. koreanum. The sequence of activity of fat-soluble inhibitor in seed coat was: V. burejaeticum＞V. mongolicum ＞V. koreanum＞V.sargenti. The sequence of activity of fat-soluble inhibitor in endosperm was: V. sargenti＞V. koreanum＞V. mongolicum＞V. burejaeticum. In conclusion, the endogenous inhibitors of V. koreanum, V. burejaeticum (distributed in the endosperm) and V. sargenti (distributed in the seed coat) were mainly fat soluble substances. The endogenous inhibitor of V. mongolicum (distributed in the endosperm) was water soluble substances.