Bio-module sand barrier was a new type sandbag barrier, it had three functions of windbreak and sand fixation, local soil improvement and vegetation establishment at the same time. Different with other sandbag barrier, its external material was jute fibre, sand soil, corn cob and sheep manure were added. To understand the function of local soil improvement of bio-module sand barrier from the angle of soil microorganisms, soil bacteria, fungi and actinomycetes number distribution in the sand barrier and around soil were determined and studied. The results showed that soil bacteria, fungi, actinomyces and total number of three in bio-module sand barrier reached 2.41×10⁷ cfu·g^-1, 4.51×10⁷ cfu·g^-1, 1.19×10⁷ cfu·g^-1 and 8.11×10⁷ cfu·g^-1 respectively, but the control were only 1.56×10⁶ cfu·g^-1、3.01×10⁶ cfu·g^-1、1.26×10⁶ cfu·g^-1 and 5.83×10⁶ cfu·g^-1; The microorganisms number of bio-module sand barrier inside soil were higher than bio-module sand barrier coverage below soil, and soil microorganisms of every layer below were higher than no bio-module sand barrier sand dunes significantly; In the range of bio-module sand barrier windward 50 cm to leeward side 50 cm, the order of the total microorganisms number was placement of the barrier>leeward side 20 cm of sand barrier>windward leeward side 20 cm of sand barrier>leeward side 50 cm of sand barrier>windward leeward side 50 cm of sand barrier, the average value of soil bacteria, fungi and actinomycetes number of this protection zone soil were 19.56, 24.47 and 8.39 times of that in mobile sand dunes. After 5 years of bio-module sand barrier set, three kinds of micro-organisms number of sand barrier inside soil were higher than its surrounding soil that illustrated bio-module sand barriers still existing potential effects on microorganisms of around bio-module sand barriers soil.