A radiator, adopted on electronic devices with radiator fans installed in series, includes a case, two or more radiator fans and a membrane check valve. The radiator fans are located on the inner wall surface of the case. The membrane check valve has a frame, at least one bracing bracket and membrane petals. The frame is located between the radiator fan and the inner wall surface of the case. The bracing bracket is located in the frame to form a plurality of cells with the frame. The membrane petals' one end attaches to one side of the frame and is more directed towards air outlets of the radiator fans than the bracing bracket. When any radiator fans stops operation, air inside the electronic devices flow outwards in the positive direction to balance the pressure and prevent heat dissipation efficiency of the electronic devices from dropping excessively.