In this paper,the authos applied Grey system theory to judge on the effect of the environmental factors on the growth and development of straw mushroom.The result showed that the best treatments are A_2 B_2 C_2 D_1 E_1 and A_4 B_1 C_2 D_2 E_1 And straw mushroom cultural appropriate conditions are cotton waste,pH8.0~8.5,CO_2 concentration< 0.2% etc.