Abstract: To study the feasibility of spent mushroom compost and peat substitute, the physi-chemical properties of the peat and spent mushroom compost were compared, and growth barrier factors of spent mushroom compost were analyzed and adjusted. The results indicate that spent mushroom compost has more larger-size particles, more air pores, better permeability, less water-holding pores than peat. So it need less water volume and more times, but it’s water losing rate is lower than peat. The velocity of capillary water upward movement of spent mushroom compost is higher than peat, and the effect of wetting agent on spent mushroom compost is not significant. Spent mushroom compost has similar moisture retention curves with peat. The nutrient retention property of spent mushroom compost is lower than that of peat, so the frequency of fertilization need to be increased. Electronic conductivity value of spent mushroom compost is high, but the one of peat is low, so the EC value of the former can be adjusted by mixing with peat in proper proportion or washing with water. pH value of spent mushroom compost is high, but it can be lowered by adding sulfur powder as well as dilute sulfuric acid or mixing with peat. If spent mushroom compost is properly adjusted and some management measures are changed, it can act as the part of peat substitute in soilless culture.