Abstract: According to the engineering geological conditions,as well as the deformation and failure characteristics of the floor roadway of No.11 coal seam in Zhujixi coal mine,combining with the multistage support features of U-steel support,the rock bearing mechanics model for support-surrounding rock of U-steel support has been built,and the force characteristics of U-steel under the condition of deep soft rock were analyzed.Based on the calculation and verification of the capacity of the support,distribution characteristics of bending moment,shear force and axial force were obtained.The location of stress concentration distribution was determined,and the buckling deformation of U-steel support was analyzed.The reinforcement scheme of U-steel support with weak intercalated layers has been put forward,that support method for longitudinal steel girder with anchor cables to the 3 key parts including the middle of the leg,the shoulder hole and middle of arch beam.The overall bearing performance of the surrounding rock was improved,and the support of repaired roadway has achieved good results.