This paper studied the inhibition role of water extracts from Allium tuberosum on Fusarium oxysporum f. sp. conglutinans（Foc）and control effect of pot cultivation by combining in vitro antibacterial assay with potted plant measurement. The result indicated that extracts could clearly suppress mycelia growth and spore germination．The inhibition rate was up to 100% when the concentration of waterextracts reached 0.75 g·mL^-1. The spore germination inhibition rate reached 95.47% when the added leek extract concentration came to 0.25 g·mL^-1 and was deal with 20 hours. In pot experiments， the disease control efficiency can reach 40%，and mortality fell by 27% 15 days after the treatment when the concentration of waterextracts reached 0.086 g·g^-1 in the culture substrate.