A control valve, used for controlling a flow rate of a fluid in a fluid passage, wherein the control valve comprises: a valve body, having an internal cavity, the internal cavity having an inlet passage and an outlet passage; a first valve assembly, disposed between the inlet passage and the outlet passage, the first valve assembly comprising: a valve seat, being in the shape of a cylinder having an opening at one end, and being fixed relative to the valve body, wherein a circumferentially extending opening is provided in a sidewall of the valve seat; a slider, disposed inside the valve seat and being movable in a circumferential direction of an inner wall of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the circumferential direction, but being stationary relative to the valve seat in an axial direction of the valve seat; a regulating valve plug, being in the shape of a cylinder having an opening at one end, being arranged to surround the valve seat concentrically, and being movable in the axial direction of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the axial direction; a first valve stem, being connected to the slider and the regulating valve plug, and having one end extending out of the valve body, wherein an amount of overlap of the slider and the opening in the circumferential direction and an amount of overlap of the regulating valve plug and the opening in the axial direction are changed by means of the first valve stem, characterized in that the control valve further comprises a second valve assembly, disposed between the inlet passage and the outlet passage, and separated in space from the first valve assembly, the second valve assembly being a pressure difference balancing valve, capable of regulating a flow rate according to the difference between a first fluid pressure and a second fluid pressure, wherein the first fluid pressure is a pressure at the inlet passage, and the second fluid pressure is a fluid pressure between the first valve assembly and the second valve assembly. a valve body, having an internal cavity, the internal cavity having an inlet passage and an outlet passage; a first valve assembly, disposed between the inlet passage and the outlet passage, the first valve assembly comprising: a valve seat, being in the shape of a cylinder having an opening at one end, and being fixed relative to the valve body, wherein a circumferentially extending opening is provided in a sidewall of the valve seat; a slider, disposed inside the valve seat and being movable in a circumferential direction of an inner wall of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the circumferential direction, but being stationary relative to the valve seat in an axial direction of the valve seat; a regulating valve plug, being in the shape of a cylinder having an opening at one end, being arranged to surround the valve seat concentrically, and being movable in the axial direction of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the axial direction; a valve seat, being in the shape of a cylinder having an opening at one end, and being fixed relative to the valve body, wherein a circumferentially extending opening is provided in a sidewall of the valve seat; a slider, disposed inside the valve seat and being movable in a circumferential direction of an inner wall of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the circumferential direction, but being stationary relative to the valve seat in an axial direction of the valve seat; a regulating valve plug, being in the shape of a cylinder having an opening at one end, being arranged to surround the valve seat concentrically, and being movable in the axial direction of the valve seat, in order to partially or completely block the opening in the sidewall of the valve seat in the axial direction; a first valve stem, being connected to the slider and the regulating valve plug, and having one end extending out of the valve body, wherein an amount of overlap of the slider and the opening in the circumferential direction and an amount of overlap of the regulating valve plug and the opening in the axial direction are changed by means of the first valve stem, characterized in that the control valve further comprises a second valve assembly, disposed between the inlet passage and the outlet passage, and separated in space from the first valve assembly, the second valve assembly being a pressure difference balancing valve, capable of regulating a flow rate according to the difference between a first fluid pressure and a second fluid pressure, wherein the first fluid pressure is a pressure at the inlet passage, and the second fluid pressure is a fluid pressure between the first valve assembly and the second valve assembly.