A high efficiency sliding screw driver is introduced. It can improve driving efficiency obviously. As the material strength of the nut in this structure is low and the nut is the most dangerous part, so it is important to master the structure’s characters of deformation and stress. The deformation and stress of this structure are researched by finite element method(FEM), and the changing law of stress concentration coefficient of the structure is gained. So the exact stress of nut teeth with highest load can be calculated directly based on this result. A the high strength sliding screw driver is introduced. As the material strength of the nut in this structure is low and the nut is the most dangerous part, so it is important to master the structure’s characters of deformation and stress . The deformation and stress of this structure are researched by finite element method (FEM), and the changing law of stress concentration coefficient of the structure is gained. So the exact stress of nut teeth with highest load can be calculated directly based on this result .