The invention discloses a fermentation medium. The fermentation medium is used for Nemadectin fermentation. According to the fermentation medium, soybean oil is used as a carbon source, and a pH valueof the medium is 7.0-7.5; and the concentration of the soybean oil in the medium is 0.25-5.0g/L. The invention further discloses a fermentation technology of the Nemadectin. The soybean oil is addedin the process of producing the Nemadectin in blue-gray streptomyces, thallus synthesis can be effectively improved, accumulation of biomass and production of products are facilitated, and the yield of the target product Nemadectin is effectively improved.