The invention belongs to the technical field of fungus cultivation, and particularly relates to a mushroom culture medium and a preparation method thereof. The mushroom culture medium is composed of the following raw materials by weight: 35-40 parts of vernicia fordii sawdust, 15-25 parts of corn cob, 8 to 12 parts of bran, 8 to 12 parts of beet pulp, 0.5 to 2.5 parts of wormwood, 1.5 to 3 parts of astragalus, 1.5 to 2.5 parts of sophora flavescens, 8 to 12 parts of shell powder, 6 to 10 parts of lotus leaf powder, 1 to 3 parts of potassium sorbate and 55 to 65 parts of water. The preparationmethod of the mushroom culture medium consists of the following steps: (1) pulverizing the vernicia fordii sawdust, corn cob, bran, beet pulp, wormwood, astragalus, and sophora flavescens; (2) addingthe shell powder, lotus leaf powder and potassium sorbate to the pulverized raw materials; (3) mixing uniformly with water; (4) performing high temperature steam sterilization after packaging; and (5)make vents in a packing strap. The culture medium of the invention can provide a good nutrient and space environment for the growth of the mushroom, accelerate the growth rate of the mushroom hyphaeand increase the biomass of the hyphae, the growth of the mushroom hyphae is good, and the preparation method is simple.