The invention provides a pressure regulating valve. An annular cavity is formed between a second sliding part of a valve core and a second guiding part of a valve core sleeve, and when the annular cavity is filled with high-pressure liquid, self pressure of the high-pressure liquid is used for respectively providing upward liquid pressure and downward liquid pressure for the valve core. The inner diameter of a second channel of the second guiding part is smaller than that of a first channel between the second guiding part and a first guiding part, therefore, action force exerted on the valve core sealing sleeve by the high-pressure liquid in the annular cavity is larger than that exerted on the second sliding part of the valve core by the high-pressure liquid, so that pressure difference, between the second sliding part and a sealing part, of the high-pressure liquid form resultant force exerted on the sealing part, the resultant force is smaller than the self liquid pressure of the high-pressure liquid, at the moment a spring only needs to overcome the resultant force which is generated by the high-pressure liquid and exerted on the sealing part, opening and closing of the pressure regulating valve can be achieved, and therefore pretightening force of the spring of the pressure regulating valve is reduced.