Abstract: Effects of four culture media (soil, sponge, sand and liquid) on the results of allelopathic potentials of dwarf lilyturf (Ophiopogonjaponicus) seedlings against Bidens pilosa L. were investigated. The results showed that the effects of different concentration (140, 1200, and 1400) of leaf extracts from dwarf lilyturf on the growth of B. pilosa were significantly different among the four culture media. Meanwhile, the root morphological structure (root length, root surface area and root volume, etc.) of B. pilosa also differed when the plants were cultivated in different culture media. Seletion of culture medium could significantly affect the outcomes of study.