The utility model relates to a gas balanced type beam -pumping unit hydraulic control system, it includes the working connection module, mend oil circuit module and execution and control module, the working connection module includes main motor, main hydraulic pump, magenetic exchange valve, double - direction hydraulic - clock, the overflow valve, an unidirectional valve, filter and oil tank, the check valve is connected with overflow valve and magenetic exchange valve, mend the oil circuit module including mending oily motor, the slippage pump, the overflow valve, an unidirectional valve, the manometer, energy storage ware and oil tank, be equipped with overflow valve and manometer between check valve and the energy storage ware, carry out and include the combination pneumatic cylinder with control module, the movable pulley, the fixed pulley, the belt, the polished rod eye, load and last, lower stroke switch, the piston rod of combination pneumatic cylinder is connected with the movable pulley, the belt with move, the fixed pulley cooperation, the energy storage ware is connected with the benefit oil pocket of combination pneumatic cylinder, double - direction hydraulic - clock's the both ends and the two upper and lower chambeies of combination pneumatic cylinder are connected, beneficial effect: adopt the combination pneumatic cylinder to balance jointly with the energy storage ware, the operation is steady, safe and reliable.