Abstract: Taking Pleurotus pulmonarius as test material, mulberry branch sawdust was used as the primary raw material to partially replace cottonseed shell to cultivate P.pulmonarius.Seven culture medium formulas with different mulberry branch sawdust contents were set up to study the effects of different mulberry branch sawdust addition ratios on the quality and yield of Pleurotus pulmonarius,in order to screen suitable formulas for low-cost cultivation of Pleurotus pulmonarius in the tropics.The results showed that with the increase of the amount of mulberry sawdust,the time of mycelium filling in bag was delayed,the cost of raw materials was reduced,while the yield and biological dfficiency of P.pulmonarius were improved.When the addition ratio of mulberry sawdust was 30%,the yield of P.pulmonarius was the highest,while the ratio of mulberry sawdust was 35%,the production profit was the highest.Therefore,the formula 4（35% mulberry sawdust,25% cotton seed hull,20% corncob,18% bran,2% lime）was the most suitable formula for the cultivation of P.pulmonarius．