Novel pressure reducing valve

The utility model relates to a novel pressure reducing valve. The pipeline structurally comprises a pipeline main body, one part of the pipeline main body is a water inlet pipe; the water inlet pipe is connected with the water outlet pipe at the rear end through a water passing hole; the water passing opening is a circular through hole; a cylindrical control piston head for controlling the water outlet flow is arranged at the circular through hole; the water inlet pipe is connected with a pressure bin of the upper end automatic adjusting device through a communicating pipe. Under the conditionthat the pressure of the front end of an existing valve is changed; the size of the opening of the valve is nonlinearly related within a certain range along with the pressure change; and the pressureof the nonlinear section is balanced, so that the equivalent area of the opening of the piston head is positively correlated with the pressure of the front end, the stability of the pressure of the rear end is ensured to the