The invention provides a liquid fermentation method of paecilomyces lilacinus. The method comprises the steps of activation of culture, expanding cultivation of culture and fermentation. According to the fermentation step, an adopted fermentation medium comprises cottonseed cake powder, kieselguhr, yeast extract powder, sweet potato powder, white granulated sugar, fish peptone, olive oil, mannitol, magnesium sulfate, copper sulfate, polysorbate 20, calcium hydrophosphate, boric acid, bile salt, tyrosine, manganese dioxide and deionized water. According to the step of activation of culture, an adopted medium for activation of culture comprises algal polysaccharides, sorbitol, beef extract, asparagine, brochantite, manganese dioxide, sodium chloride, calcium chloride, boric acid, ferric citrate, mannitol, agar and deionized water. According to obtained paecilomyces lilacinus fermentation liquid, the content of spores is 4.1*10<9>-4.4*10<9>/g.