Abstract: The inexpensive raw material soybean molasses（Sm） was used as exogenous additive materials to study the effects of different Sm additions on Hypsizygus marmoreus liquid spawn quality by determination and comparison of physiological and biochemical indexes including biomass, mycelial pellets morphology, glucose consumption rate, extracellular enzyme activity, mycelial growth rate, and fruiting yield, in order to provide reference for the high-value utilization of the inexpensive raw material Sm on H.marmoreus liquid spawn preparation.The results showed that Sm proper addition level was 1% in liquid culture medium.Addition of 1% Sm could improve glucose consumption rate and mycelial growth performance.Stable growth phase of H.marmoreus liquid spawn advanced to 6 days with more biomass obtained comparing to the contrast.The apparent quality of liquid spawn was significantly improved with uniform diameter of mycelium pellets and burr-free on surface.Physiological and biochemical activity of liquid culture medium determination results showed that activity of xylanase, cellulase and laccase increased due to H.marmoreus accelerated secretion extracellular protein with Sm addition.In particular, the activity of laccase was 30.4 times that of the control, in order to degrade phenolic acids in Sm, which lead to the pH of liquid culture medium increased rapidly.Furthermore, mycelial germination was fast and 5.3% increased of average growth rate than the contrast.Finally, fruiting test showed mycelium fulfill the bag advanced 4-9 days and fruiting yield increased 6.9% by using Sm liquid spawn comparing to the contrast.The experiment showed that addition of 1% Sm in the liquid culture medium could shorten the liquid spawn preparation time and effectively improve the quality.