Abstract: Allelopathy plays an important role in biological invasion. In this study, the invasive plant Oxalis corymbosa DC was used as donor plant, Lolium perenne L., Bidens pilosa L. and Celosia argentea L. were used for receivers, petri dishes with filter paper were used to examine allelopathic effects of aqueous leachates of the roots, stems and leaves of O. corymbosa. The results showed that aqueous leachates of the roots, stems and leaves inhibited seed germination and seedling growth of all the three weed species. The inhibitory effect increased with of the concentration aqueous leachates from 0.05 g/mL to 0.20 g/mL.