The invention discloses a sodium hydroxide dosing device. The sodium hydroxide dosing device comprises a solution tank and liquid distribution metering systems, wherein a stirring motor is arranged in the middle of the top of the solution tank; an output end of the stirring motor is connected with a stirring device; a blow-down pipe is arranged in the middle of the bottom end of the solution tank; a ball valve I is arranged on the blow-down pipe; a liquid outlet pipe is arranged on the side face of the lower end of the solution tank; the liquid outlet pipe is provided with a liquid distribution pipe I and a liquid distribution pipe II; the liquid distribution pipe I is provided with a ball valve II; the liquid distribution pipe II is provided with a ball valve III; two sets of liquid distribution metering systems are arranged; one set of the liquid distribution metering system is connected with the liquid distribution pipe I and the other set of the liquid distribution metering system is connected with the liquid distribution pipe II; a chemical feeding hole is formed in the top of the solution tank; a water feeding hole is formed beside the chemical feeding hole; a liquid level meter is arranged on an outer wall of the solution tank; each liquid distribution metering system is composed of a Y-shaped filter, a metering pump, a safety valve, a metering pump liquid outlet pipe, a pressure detection pipe and a medicament outlet pipe. The applicable occasion is enlarged and the chemical dosing precision is improved.