The invention discloses a pressure control system and method with a pressure test medium capable of conducting bidirectional flow, and belongs to the technical field of hydraulic tests. The pressure control system comprises a container to be tested and a water tank. At least one pressure control pipeline is connected between the container to be tested and the water tank. Each pressure control pipeline comprises a plunger cavity, a liquid inlet pipe and a liquid outlet pipe. The plunger cavities are internally provided with plungers in a matched mode. The plunger cavities are connected to the container to be tested through the liquid outlet pipes. The liquid outlet pipes are provided with water outlet stop valves. The plunger cavities are connected to the water tank through the liquid inlet pipes, and the liquid inlet pipes are provided with water inlet stop valves. According to the pressure control system and method, the stop valves forced to be opened and closed are utilized to replace water inlet valves and water outlet valves, the plungers are controlled to move through pressure feedback so that the medium can flow forward and reversely, and the purpose that the rate of pressure rise and the rate of pressure reduction can be effectively controlled is achieved; the pressure can be controlled more precisely, and the control accuracy reaches +/-0.02 MPa; automatic pressure supplement or pressure reduction is achieved so as to achieve stable control over the pressure; the technological level of a traditional pressure test technology is broken through.