Abstract: The paper,taking the thick seam mining roadway at 347 working face of a mine in Henan as research object,research deformation and distribution situation of plastic zone of U-steel supported roadway surrounding rock under great horizontal stress by using theoretical analysis,numerical calculation, field observations and other methods.The results show that the plastic zone at the top range of roadway is shallow,at the side and bottom is deeper relatively,and the maximum deep reached 3 m;the larger deformation is relatively at the bottom,maximum amount of floor is 260 mm. For roadway deformation features of u-steel support under great horizontal stress,the existing support system is optimized by using high-strength bolt to reinforce support of the roadway side and bottom,numerical simulation and industrial applications show that the improved support method has a good effect on controlling surrounding rock deformation.