In the process of functional testing of the lifting support system in a large microwave anechoic chamber,it was found that the torque of the lifting mechanism was too large due to the accelerated decent or emergency stop of the system,which would cause the failure of the transmission mechanism or other unsafe hidden dangers.To solve the above problems,a special hydraulic rail holding device was installed on the side of the system lifting guide rail.The results show that when the support system stops or stops suddenly,the linear guide rail is clamped firmly by the rail holding device,it can ensure the positioning stability and accuracy of the support system and avoid the impulsion and damage to the guide rail and transmission mechanism,so as to improve the safety and reliability of the lifting support system.