By using orthogonal design, this paper investigated the growth of cultured prairie milk vetch (Astragalus adsurgens) root on the B5 medium with different contents of sucrose, macro-and microelements and organic supplements, and adopting the method of filter paper-culture in Petri-dish, studied the effects of A. adsurgens culture filtrate on the seedling growth of radish (Raphanus sativus) and wheat (Triticum aestivum). The results showed that the effect of A. adsurgens culture filtrate on R. sativus and T. aestivum seedling growth was of allelopathic, and nutritional stress might be the important cause of A. adsurgens allelopathy.