The invention discloses a method for improving yield and activity of fermentation products of agaricus blazei murill liquid, comprising the following steps of: 1, extracting traditional Chinese medicines composed of, weight: 5-30 parts of dogwood, 5-30 parts of dried rehamnnia root, 5-30 parts of liquorice root and 5-30 parts of ginkgo leaf through aqueous solution, to get traditional Chinese medicine compound water extraction liquid; 2, adding the traditional Chinese medicine compound water extraction liquid, bilobalide and cane sugar aliphatic ester to fermentation foundation medium to get agaricus blazei murill fermented medium; 3, adding agaricus blazei murill culture to agaricus blazei murill mediume prepared in step 2 to get fermented solution through liquid fermentation, and separating to get fermented product. The method for improving yield and activity of fermentation products of agaricus blazei murill liquid adds traditional Chinese medicine compound extracts such as dogwood, dried rehmannia root, liquorice root and ginkgo leaf as well as bilobalide and cane sugar aliphatic ester based on features of agaricus blazei murill culture, to obviously improve biomass and polysaccharide yield of agaricus blazei murill, and obviously improve activity of polysaccharide.