Abstract: Via the method of the sterilized raw material cultivation,Pleurotus ostreatus ‘New 831’ was used as the experimental material,the effects of nine content of the spent mushroom substrate（SMS） of factory-cultivated Flammulina velutipes（0%,10%,20%,30%,40%,50%,60%,70% and 80%） on the physiochemical property of culture substrate,the agronomic traits and nutritional component of P.ostreatus were studied,thus to obtain the optimal F.velutipes SMS content for P.ostreatus cultivation.The results showed that C-N ratio,water content of culture media,mycelial growth vigor gradually reduced with the increasing content of SMS.While the mycelial growth rate increased firstly and then decreased with the SMS content increased.The biological efficiency of the treatment groups were all higher than that of the control group.In addition,with increasing content of SMS,the biological efficiency also increased firstly and then decreased,while the highest biological efficiency was obtained at 50% SMS.Addition of SMS could remarkably improve the nutritional component of P.ostreatus fruiting bodies.The comprehensive results indicated that the optimal content of F.velutipes SMS for P.ostreatus cultivation was 50%.