Abstract: Taking soybean straw and corn cob as raw materials to cultivate Pleurotus ostreatus,the optimum water content and filling amount of the selected formula were optimized by formula optimization and pouch preparation experiments, in order to provide reference for the mixed cultivation of Pleurotus ostreatus with soybean straw and corn cob.The results showed that the highest biological efficiency of fruiting body was 104.33% when Pleurotus ostreatus was cultivated with 40% soybean straw, 40% corn cob, 12% bran, 5% soybean meal, 2% lime and 1% light calcium carbonate.The biological efficiency was 104.53%-110.50% when the ratio of materials to water was 1∶1.7-1.9 g·mL^-1 and the amount of dry material was 0.50 kg·bag^-1（size of fungus bag, 18 cm×35 cm）,and the net profit was 0.24-0.39 RMB·bag^-1 higher than that of the control group.