Abstract: In order to improve the reliability of hydraulic support,the actual use situation of ZY21000/38.5/83D hydraulic support was analyzed.The simulation model of hydraulic support shield beam was simulated and demonstrated.The fallen roof pressed at the back end of the top beam and the hinge beam and the front end of top beam is not connected.The hydraulic support reaches the mechanical limit position of top beam and shield beam.At this time,the top beam and the cover beam are almost in a straight line to form an anti-aircraft gun state.Damage to the shield beam structure caused by periodic pressure.Based on this,the leverage model for the failure of the shield beam is proposed and the simulation analysis of the model is carried out.The conclusion that the shield beam is easy to fail under the leverage model is obtained.Coal mine production operations should avoid the use of hydraulic supports,especially large mining height brackets,in this leverage model attitude.Finally,preventive measures to avoid failure of the hydraulic support shield beams are proposed.