Abstract: The active components of edible mushroom could be obtained efficiently by direct induction using the liquid fermentation culture medium. In this research, a liquid culture medium inducing the enrichment of ganoderma acid A was designed to induce the enrichment of triterpenoid of ganoderma acid A. The single factor experiments were employed to research the effects of carbon source, nitrogen source and growth factor in culture medium on the production of ganoderma acid A, therefore the components and contents of culture medium were determined. The formula of medium inducing the enrichment of ganoderma acid A was determined as follows: glucose of25～30 g/L, histidine of 0.5～0.7 g/L, and complex vitamins B of 10～50 mg/L.