The invention discloses an elevator composite counterweight grinding ultraflat production line. The production line comprises a loading platform, a unloading platform, an operation platform and an electric control console; the operation platform includes a moving mechanism, a host machine body, and guide columns arranged on two sides of the host machine body; bearing bases are arranged on the guide columns; main shaft boxes are arranged on the bearing bases; lifting lead screws and driving shaft motors are arranged in the main shaft boxes; belt wheels are arranged on output shafts of the driving shaft motors, and are connected with main shafts through power belts; diamond grinding wheels are arranged at the lower ends of the main shafts; the loading platform includes a loading mechanical roller way frame on one side of the host machine body; the unloading platform is arranged on the other side of the host machine body; and the unloading platform includes a unloading roller way provided with multiple rotating rollers. The production line has the advantages of reasonable structure design, convenience for operation, capability of largely relieving the labor intensity of workers, improvemeent of the working environment, reduction of the enterprise production cost, effective guarantee of the product flatness and the size precision requirement and improvement of the production efficiency.