Abstract: The complex occurrence conditions of steeply dipping coal seam affect the safety and stability of the support. At present, the most critical problem facing mining with large dip Angle working face is to ensure the stable work of the support. Based on the analysis of mechanical behavior of φ160/105-730 bedload jack in a large dip coal seam, and the bidirectional transient fluid-structure coupling analysis of bedload jack with the help of ANSYS Workbench software, this paper obtains the stress and strain characteristics of the bedload jack of hydraulic support. Combined with the actual working conditions, The analysis shows that the failure of the cylinder water flowing of the push jack is easy to occur at the junction of the piston rod and hydraulic oil and the push jack cylinder block. The thickness of the cylinder block at the junction of the piston rod and the cylinder block should be properly thickened, and the seal at the junction of the piston rod and the cylinder block should be strengthened, which provides a guarantee for the stability of the hydraulic support and the safety of the coal mining space on the large Angle working face.