Auger mining machine which is used in thin coal seam gets coal by drilling. Its drilling distance always is dozens of meters. Because of the long Drilling distance, the deflection of the drilling tool was produced by deviating force . In order to improve auger mining machine’s preventing deflection character and scope of application, the research on preventing deflection mechanism of auger mining machine combining theoretical analysis and experimental research was carried out on the basis of a simplified drilling tool structure. The studies we have performed showed that: increasing the drilling assembly bending rigidity or the drill pipe weight can prevent deflection; reducing the distance between the drilling stabilizer and drill is another method to reduce amount of deflection.