Abstract: The paper aims to research the allelopathy effect of Alternanthera philoxeroides on turf grass. With three kinds of warm-season turf grass (Zoysia pacifica, Axonopus compressus and Cynodon dactylon) as test materials, dish-dipping method was used to explore the allelopathic effects of different concentration s’aquatic lixivium and extracts from Alternanthera philoxeroides on seed germination and early seedling growth of the three kinds of warm-season turf grass. The results showed that lternanthera philoxeroides had inhibitory effect on Zoysia pacifica seeds germination and the effect tended to increase with the increase of the concentration of the aquatic lixivium and the extracts; the result of Axonopus compressus germination indicated that the concentration of 0.25 g/mL and 0.125 g/mL had promoting effect, whereas the concentration of 0.0625 g/mL and 0.5 g/mL had inhibitory effect. For Cynodon dactylon, it showed that high-concentration had inhibitory effect and low- concentration manifested promoting effect. Therefore, the study reveals that Alternanthera philoxeroides has allelopathic effect through releasing allelochemicals into the surrounding environment to affect seed germination and early seedling growth.