The invention discloses a high-rise building maintenance robot. The robot comprises a base, a grinding mechanism supporting base, four climbing parts, a repairing part and a grinding part, and is characterized in that two first slide blocks of the grinding mechanism supporting base are slidably installed in two second dovetail grooves in the front of the base respectively, and a first gear is meshed with a second rack; a triangular base shaft and a tripod rotary shaft of the grinding part are rotatably installed in round holes in the lateral surfaces of two first supporting plates; a second stepping motor drives the triangular base shaft to choose from different grinding wheels, third gears are driven to be shrunk through four ninth hydraulic cylinders, so that third gears are meshed with fourth gears, a fifth stepping motor drives the fourth gears, and the first grinding wheel or a second grinding wheel or a third grinding wheel is driven to grind, the machine conducts grinding through different grinding wheels, the grinding precision is improved, and the work efficiency is improved.