The utility model discloses a constant-lift guide valve of a hydraulic control valve, which comprises a spring sleeve body, an upper valve body and a lower valve body. The upper valve body is providedwith a first connection opening; the lower valve body is provides with a second connection opening, a third connection opening and a fourth connection opening; the first connection opening is communicated with a first cavity body which is arranged at the upper valve body; a diaphragm, a lower supporting plate, an upper spring, an upper pressing plate and an adjusting bolt are sequentially arranged above the first cavity body; an upper valve core, a lower valve core and a lower spring are sequentially arranged below the lower supporting plate; and the upper valve body is fixedly connected withthe lower valve body. The guide valve can realize the functions of controlling the opening degree of the hydraulic control valve and leading upstream pressure of the hydraulic control valve to be constant. When the hydraulic control valve with the guide valve is installed at the outlet end of a water pump, the guide valve can adapt to the dynamic changing of pipe network pressure (downstream) toautomatically adjust the upstream pressure, so as to lead lift of the water pump to be constant, thereby leading flow rate of the water pump to be constant. Meanwhile, the guide valve can lead a modelselection working condition point of the water pump to be constant, and make sure the water pump cannot lead overload on driving equipment when working in a high-efficiency zone.