The invention relates to a power battery water-cooling plate for brazing. The power battery water-cooling plate comprises an upper plate and a lower plate, wherein the upper plate is buckled with thelower plate, the upper plate and the lower plate are fixed by brazing, a runner is formed between the upper plate and the lower plate and is used for a cooling liquid to flow, the runner comprises a liquid inlet runner and a liquid return runner which are arranged in parallel, an inlet and an outlet of the runner are arranged in parallel, a liquid inlet is formed in a position, corresponding to the inlet, of the upper plate, and a liquid outlet is formed in a position, corresponding to the outlet, of the upper plate. The power battery water-cooling plate is formed by only combining the upper plate and the lower plate, is simple in structure, good in pressure resistance, light in weight and high in heat exchange efficiency and is difficult to leak; by arranging the liquid inlet runner and the liquid outlet runner in parallel, the thermal equalization performance of a battery module is greatly improved; and the upper plate and the lower plate are fixed by brazing, the production efficiency is high, the weight of a battery module water-cooling system is reduced, the heat exchange capability of the water-cooling plate is improved, good temperature uniformity is achieved, and the powerbattery water-cooling plate is suitable for rapid production on a large scale.