The invention provides a pressure reducing valve capable of outputting pressure selectively. The pressure reducing valve comprises a valve body, an adjusting spring, a piston rod and a feed valve, wherein an input cavity and an output cavity are formed in two sides of an air feed valve respectively, the two ends of the piston rod are connected with the feed valve and the adjusting spring, two pressure precontrol cavities are arranged above the output cavity in sequence, a lower diaphragm plate of each pressure precontrol cavity is larger than an upper diaphragm plate of each pressure precontrol cavity in area, an air inlet of each pressure precontrol cavity is connected with an air source through a solenoid valve, the piston rod penetrates through the upper diaphragm plates and the lower diaphragm plates of the two pressure precontrol cavities, and the piston rod, the upper diaphragm plates and the lower diaphragm plates are fixed and sealed. According to the pressure reducing valve capable of outputting the pressure selectively, the required pressure can be adjusted automatically according to system requirements, the adjusting spring can be used for setting initial pressure, when the pressure can not meet the system requirements, the solenoid valves act to increase the precontrol pressure of the pressure reducing valve, and therefore the function of increasing pressure output is achieved; the two solenoid valves act together to realize the adjustment of output pressure, the solenoid valve which is needed for work is selected according to the system requirements for pressure, therefore, work efficiency is improved, energy sources are prevented from being wasted, and multilevel pressure output is realized.