In the process of rolling plate, the huge impact force and axial movement force of work roll produced by using the rolling mill will be transferred to the pressing cylinder, thus causing frequent damage to the seal of hydraulic cylinder.In view of the above problems, through optimization and improvement, the response speed of AGC hydraulic system was improved and the roll shape was adjusted, and the bending roller action of the hydraulic cylinder was cancelled on the premise of meeting the requirements of the same plate difference and plate shape of the steel plate; through transformation,the independent oil supply of two hydraulic cylinders on the same block was realized;through the transformation, after the rod side seal was damaged, it could switched from the standby pressure oil supply to the direct oil return state, the piston rod could retract with the help of roller system movement when changing the roller.The results show that optimizing the sealing combination of piston rod and using new material can improve the working reliability of the hydraulic cylinder and reduce the use cost.