The invention belongs to the technical field of online chemical instrument signal processing in power stations and in particular relates to a sodium analyzer state monitoring device and an operating method thereof. According to the device, an injection valve is sequentially connected with a bypass valve, a flow meter and a calibration valve from bottom to top; the calibration valve is connected with a diffusion tube and arranged in an alkaline reagent bottle; the alkaline reagent bottle is connected with a measuring cup; the measuring cup is connected with a transmitter; the transmitter is further connected with an air pump and an overflow cup; the overflow cup and the measuring cup are respectively connected with a water collection tank; and the bypass valve is connected with the overflowcup. The sodium analyzer state monitoring device disclosed by the invention is used for solving the technical problem that useless over-range alarm information is frequently triggered because the on-off state of a water supply preparation system is changed during field use.