To improve cultivation technique for the stable and high yield, the outdoor fermentation of rice straw bundles, and pasteurization and fermentation of rice straw compost in tunnel were carried out. 1) Mycelial growth of P. ostreatus was becoming rapid and dense according to prolongation of fermentation periods outdoor rice straw bundles, but days untill fully mycelial growth after spawning was short. 2) As the fermentation period of rice straw bundles was 6 days (three times turning), yield of P. ostreatus was the highest as $50.5kg/3.3m^2 and increased 24% of yield than those of conventional method. 3) When it was fermented rice straw compost in tunnel for 4 days, mycelial growth of P. ostreatus was rapid and dense, and also days untill budding after spawning, was shorter, yield $67.6kg/3.3m^2$, resulted in increasing 17% of yield than those of conventional method. 4) On being sterilization and fermentation of the rice straw compost in tunnel, the production cost was decreased 22.3% in compared with conventional method.