The invention relates to a waterborne polyurethane coating for protection of concrete in cold areas and a preparation method thereof. The waterborne coating consists of a component A and a component B. The component A includes the components by weight: 40 to 70 parts of a waterborne polyurethane dispersion body, 0 to 20 parts of waterborne hydroxyl acrylic resin, 0 to 20 parts of waterborne polyurethane resin, 0 to 10 parts of a waterborne polytetrafluoroethylene emulsion, 0.1 to 8 parts of an auxiliary agent, 5 to 30 parts of pigments and fillers, and 7 to 10 parts of deionized water. The component B is a waterborne isocyanate curing agent with the addition amount of 10-15 parts. The waterborne polyurethane coating can be used normally at low temperature, can prevent concrete from occur water vapor erosion, freeze-thaw damage and other phenomena in cold climate, and slows down natural weathering speed.