Abstract：Replanting disease is a serious obstacle for sustainable development of strawberry (Fragaria ananassa Duch) at present. Effect of auto-toxicoid root exudates and decomposing liquids on activities of 2,3,5-Tripheyl Tetrazolium Chloride(TTC) reduction, superoxide-dismutase (SOD), and pathogeny of strawberry root were studied. The results showed that allelopathy of root exudates and decomposing liquids played an important role in strawberry replanting disease. Owing to the allelopathy, activities of TTC reduction and SOD of root were decreased, growth and development of strawberry seedlings could be vigor less, root resistance to soil-borne disease would decline, and colony growth and spore germinition were promoted by the allelopathy. So the replanting disease of strawberry became more and more serious.