Abstract: Allelopathic effects of aqueous extracts of Wedelia trilobata （L.)Hitchc. and Wedelia chinensis （Osbeck.）Merr. on seed germination and seedling growth of Daucus carota L. and Brassica parachinensis Bailey were investigated using the petri dish bioassays. The results showed: (1) the maximum germination rate decreased with increased concentrations of the aqueous extracts of W. trilobata and W. chinensis, and the time to reach the maximum germination rate was also delayed in varied degrees; (2) the inhibitory effect of aqueous extracts of W. trilobata on seed germination potential, germination rate and germination index of the tested plants was less than that of W. chinensis under the same concentration; (3) the aqueous extracts of W. trilobata and W. chinensis promoted the seedling growth of the tested plant at low concentrations and inhibited them at high concentrations, and the root elongation was more sensitive to the inhibitory effects of the donor materials; (4) comprehensive experiments showed that the inhibitory effect of W. chinensis on the tested plants was stronger than that of W. trilobata.