Abstract: By bioassay of germination of Phaseolus aureus，Glycine max，Cucumis sativas，Brassica oleracea and Zea mays，the allelopathic of Ferulic acid and Cinnamic acid to Chinese-fir is analyzed．The results show that the high concentration of Ferulic acid inhibits the germination of the above vegetable seeds，while with the concentrations decreasing，the inhibited effects get weak．The high concentration of Cinnamic acid inhibits the effects on germ ination of Phaseolus aureus，Glycine max, Cucumis sativas and Zea mays seeds，while with its concentrations decrea sing，the inhibited effects get weak also．However，the high concentration of Cinnamic acid shows a positive effect to Brassica oleracea．