Abstract: In order to accelerating maize straw decomposition and improving soil fertility, pot experiment was conducted to study effects of maize straw decomposition on soil available nutrient by multiple factors interaction with five treatments(CK, water, water + nitrogen, water + microorganism, water + nitrogen + microorganism). The results showed that microorganism and nitrogen supplied could mineralized organic P speedily and increased soil available P. Nitrogen fertilizer increased content of available nitrogen, in addition, nitrogen fertilizer supplied nutrition for microorganism to improve their activities, more nutrient was released from maize straw decomposition in the later period, organic K mineralization was improved，soil available K content increased by ranging from 12.62% to 18.19%. Optimal water, nitrogen and microorganism coordination could increase content of organic matter, increase by 7.62%-9.45% four months later. Compared with other treatments, take considering of soil available nutrient and soil organic matter as a whole, water + nitrogen treatment was better.