Abstract: According to the geological distribution of the main drainage chamber of the second auxiliary well in Zhangji Mine, the U-shaped steel support is designed for its weak section.The ANSYS finite element analysis software is used to construct the U-shaped steel force model, and the stability analysis is carried out to draw the stress map, displacement map, and bending moment diagram.The results show that the stress is mainly concentrated on the arch foot and the roadway ' s sides. The maximum displacement is 372.783mm at the vault. The maximum bending moment is 162kNm and it is located in the roadway ' s sides. The bending moment distribution increases linearly along the vertical direction of the roadway ' s sides.According to the analysis results, the reinforcement measures are proposed, that is, the reinforcing plates are welded on the U-shaped steel grooves, and are evenly arranged every 500 mm,the concrete is filled in the groove to increase its rigidity.Through the monitoring of the convergence of 60d surrounding rock, it is proved that the reinforcement measures have achieved good results.