The invention belongs to the field of household appliances, and especially relates to an automatic pressure-stabilizing descaling water heater. The water heater comprises a water tank, a heating pipe,a heating pipe and a water outlet pipe. The heating pipe is arranged at the inner top surface of the water tank, the water inlet pipe and the water outlet pipe fixedly communicate with the upper endand the lower end of the water tank, two sliding blocks with U-shaped sections are arranged in the water tank, the two sliding blocks are symmetrically arranged relative to a heat receiving pipe and are in sealed sliding connection with the side wall of the water tank, an upper plate and a lower plate are arranged between the two sliding blocks, the opposite faces of the upper plate and the lowerplate are connected with the inner side walls of the sliding blocks through extension springs and are in sealed sliding connection with the side walls of the sliding blocks, permanent magnets with thesame polarity attracting each other are fixedly embedded in the opposite side walls of the upper plate and the lower plate, a plurality of upper through holes are formed in the upper plate, a plurality of stand columns matched with the upper through holes are arranged on the lower plate, and a plurality of lower through holes are formed in the lower plate. By arranging the descaling mechanism, scale on the heating pipe is scraped off along with up-down movement of an induction coil on the heating pipe, and cleanliness of the heating pipe can be effectively guaranteed.