Drooping wildryegrass (Elymus nutans) has been widely planted together with other perennial grasses for rebuilding degraded alpine meadow atop the Tibetan Plateau. However, the rebuilt sown pastures begin to decline a few years after establishing. One of the possible causes for degradation of sown grassland may come from allelopathy of planted grasses. The purpose of this study was to examine allelopathic potential of drooping wildryegrass. Three types aqueous extracts from drooping wildryegrass and its root zone soil were prepared and 5 highland crops and 5 perennial grasses were used as recipient plants. Drooping wildryegrass exhibited strong allelopathic potential on germination and seedling growth of 5 crops germination and growth, but different crops or perennial grasses respond to the extracts differently. The pieces extract has stronger inhibition than others. Hulless barley, oat and Chinese fescue were the most affected, while quinoa and Siberian wildryegrass were the least affected. Drooping wildryegrass presented less influence on Kentucky bluegrass and crymophylla bluegrass than on Chinese fescue. It is recommended that the species combination of mixture for restoration should consider allopathic effects of the co-seeding and decrease the seeding rate ratio of drooping wildryegrass. The annual dicot crop quinoa and rape seeds can be used as alternative subsequent crop for seed field of drooping wildryegrass monoculture.