In view of new-type tension and extension process requirements in the application of pneumatic hydraulic synchronous unloading mechanism,understanding field extension process of steel bar and problems in the using course,some relative proposals were presented for its perfection and improvement.Changing the structure and size,steel bar and PHSUM fracturing problems were overcome.Controlling the flow and time through annular clearance strictly,slow and synchronous unloading was realized.Besides,oil return check valve was designed to realize oil quick reposition.The feasibility of the optimization was verified by finite element analysis.