In this study, Medicago falcata, M. sativa and Lolium perenne were selected as the research subjects. Based on sand-culture experiments, the comprehensive effects from 12.5-50 g/L water extracts of the adult and root-tillering seedlings of Rhus typhina on the germination, seedling growth and crucial physiological indices of turfgrass were studied. The aim of this study was to clarify the differences in the allelopathic potential of R. typhina at different growth stages. The results showed that: (1) All the M. falcata seedlings died after being treated with 12.5-50 g/L extracts of all nutritive organs from R. typhina at each growth stage; (2) Based on the synthetic effects of the allelopathic effect (SEs), which were calculated based on the allelopathic effect indices of indicators directly reflecting the seed germination and seedling growth status of the receivers, extracts from the root-tillering seedlings of R. typhina presented stronger allelopathic inhibitory effects on M. sativa and L. perenne than did the adult plants, regardless of the source organ and concentration of extracts (the SEs decreased by 0.01-0.51); and (3) the source organ and concentration of the extracts, and the identity of the receivers also significantly affected the allelopathy of R. typhina. When other factors were consistent, the leaf extracts generally presented the greatest allelopathic potential (SEs=-0.86/-0.54), followed by the bark extracts (SEs=-0.56/-0.33) and the root extracts (SEs=-0.46/-0.24). The inhibitory effects of the extracts increased with increasing concentration, except for those of the extracts from the roots of adult plants, which weakened with increasing concentration. Among the two receivers that could complete seedling growth, M. sativa was more sensitive to the allelopathic inhibitory effects of R. typhina. In conclusion, the density of R. typhina root-tillering seedlings should be controlled to avoid allelopathic effects on understory turf species. L. perenne can be used as the preferred turfgrass in the R. typhina planting area.