The 200X pressure reducing valve is an intelligent valve that uses the self energy of the medium to regulate and control the pressure in pipes. The 200X pressure reducing valve can be used in domestic water supply, fire fighting water supply and other industrial water supply systems. The outlet pressure of the main valve can be regulated through the adjustment of the pressure reducing valve; the outlet pressure does not vary along with the inlet pressure and inlet flow; the outlet pressure can be safely and reliably maintained at a preset value and the preset value can be adjusted according to actual needs to obtain the pressure reducing goal. This valve is precise in pressure reduction, stable in performance, safe and reliable, easy and convenient to install and adjust, and long in service life.