The utility model discloses an empty and load adjustment valve capable of selecting output, and the valve comprises a valve body, a pressure adjustment mechanism, an air spring feedback mechanism, an actuating rod, a pressure output mechanism, a check valve, a supply valve, and a solenoid valve. The valve body is divided into an upper valve body and a lower valve body. The solenoid valve is fixed on the lower valve body, and is connected with a first feedback cavity and a second feedback cavity. The air spring feedback mechanism comprises a precontrol cavity and a second precontrol cavity. The upper valve body is provided with two air inflow channels. The supply valve moves up and down along a supply valve sleeve fixed in the lower valve body. The lower part of the supply valve and the upper part of the supply valve are respectively connected to the upper and lower ends of a supply spring. The valve provided by the utility model achieves the on-line adjustment of a curve of a required proportional relation during the braking of a train, improves the work efficiency of a system, reduces the complexity of system design, and reduces the cost of design and execution.