A pneumatic nozzle for roller coating is revealed. A workpiece to be coated is fixed on a rotating power source of a machine. A high-pressure pneumatic nozzle and a material supply nozzle, both corresponding to the workpiece, are arranged at the machine. The workpiece is driven to rotate by the rotating power source while the material supply nozzle applies coating material to the workpiece and the high-pressure pneumatic nozzle releases high pressure gas. The coating material attached on the surface of the workpiece is pushed by the high pressure gas and spread uniformly on the workpiece by rotating workpiece. Thereby the material is coated smoothly in a non-contact way and the thickness of the coating material is controlled in micron scale. This helps following manufacturing of three-dimensional microstructures on rolls for producing roll dies and increases the practical value.