Soil microorganism is an important part in forest ecosystem, which a play key role in managing soil nutrient budget, adjusting soil physical and chemical balance, clearing soil toxic substances, and as well as assisting plants in nutrient absorption. Nitrogen (N) is considered to be a limiting nutrient factor for net primary productivity in temperate forest ecosystem, which affects the changes of material and energy of soil ecosystem. Therefore, the study of the influence of N addition on the content and co...