NOVELTY - Preparation of culture medium involves pile up sawdust up to 5 - 15 meters high to undergo first fermentation process which takes 3 months; periodically turn over the sawdust pile; adding dried and sterilized cattle excrements to the fermented sawdust to undergo second fermentation process, where the sawdust pile is 5 - 15 meters high and the fermentation temperature is 70 - 90degreesC; periodically turn over the sawdust pile; and the culture medium is ready when the color of fermented sawdust turns dark brown, close to black, and the urine like ammonia odor disappears.    USE - For making culture medium for Agaricus blazei Murill mushroom (claimed); as culture medium for cultivating carpophores (fruiting bodies) of Agaricus blazei Murill mushroom.    ADVANTAGE - The two compost fermentation processes produces nutrients required for cultivating Agaricus blazei Murill mushroom and achieves good yield. The cattle excrements within the medium has fibers, minerals, and vitamins that can be absorbed by the Agaricus blazei Murill mushroom and stimulate its growth, which is able to increase the harvest yield of Agaricus blazei Murill mushroom. The grass fibers can be easily absorb by the Agaricus blazei Murill types of straw fungi and the minerals and vitamins are able to provide the required nutrients during the growth of Agaricus blazei Murill mushroom. Therefore, the harvest yield of the culture medium is 35 - 40 g of dry Agaricus blazei Murill mushroom carpophores (fruit bodies) per kilogram of two-time fermented sawdust, which is more than the outputs of other prior cultivation technologies. In addition, the two-time fermentation process can reduce the harmful elements e.g. phenol, chloride phenol, organic acid so that the cultivated Agaricus blazei Murill mushroom is not harmful to human health. The culture medium, compared to the prior art, not only facilitates the cultivation of Agaricus blazei Murill mushroom carpophores (fruiting bodies) and high harvest yield, but also produces meaty, crunchy, yet tender and refreshing product without harmful element.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a culture medium comprising two-time fermented sawdust (75%) and sterilized cattle excrements (25%).