This paper studied the quantities and fauna component of soil microorganism in shelter forest under different conditions of site, shelter forest with different ages, shelter forest in different seasons, and shelter forest composed by different kinds of plants. The results indicated that with Taklimakan desert highway shelter forest and artificial greenbelt set up under condition of irrigating by saline water, wind erosion decreases, and shifting sand was fixed, so soil structure and nutrient status was improved, and the quantities of soil microorganisms increased sharply. Among soil microorganisms,bacteria were predominant,actinomyces the next and fungi the least. There were more microorganisms in the upper soil than ones in down soil. Outside shelter forest, soil microorganisms near shelter forest have higher activity, and the quantity of soil microorganisms over 3 m from shelter forest were almost equal to ones of shifting sand.The quantities of soil microorganisms vary with seasons, and there are distinct difference among quantities of soil microorganisms of forests under different condition of site.The quantities of microorganisms and soil nutrient increase greatly with time elapse, and the change will be much more obvious.