The invention relates to a static pressure support bidirectional buffer plunger cylinder used in an energy saving system of petroleum exploitation equipment, and belongs to the mechanical engineering field. The static pressure support bidirectional buffer plunger cylinder is characterized in that a plunger rod is in clearance fit with a front seat, a piston is fixed on the plunger rod and is in clearance fit with a cylinder barrel, a buffer plunger is connected with the plunger rod by thread and the buffer plunger is in clearance fit with a base. A single-acting hydraulic cylinder with extremely low friction force is adopted in the design of the static pressure support bidirectional buffer plunger cylinder, an upper end and a lower end of the plunger cylinder need a buffer mechanism, the whole friction force requirement of the cylinder is very low, the starting pressure is required to be very low, and the plunger rod can fall off by self weight. A novel material polyfluortetraethylenewith extremely low friction force is adopted for a sealing component of the cylinder, which ensures the reliable sealing component; and a static pressure support bidirectional buffer plunger with small friction force and low energy consumption is adopted for a piston part of the plunger rod, which can collect waste energy during petroleum exploitation and apply the waste energy to the equipment, saves external energy supply and lowers self energy consumption of the equipment.