A loading device which is used in coating processes includes a base, a loading plate, and a reversing assembly. The base includes an outer frame and a ring-shaped inner frame rotatably positioned on the outer frame. The loading plate defines a number of holes for loading components. The reversing assembly connects the inner frame to the loading plate. The reversing assembly includes two reversing motors and two shafts. The reversing motors are opposite to each other and fixed on the inner frame. The reversing shafts are opposite to each other and positioned in a straight line. One end of each reversing shaft is coupled with a corresponding reversing motor, the other end of each reversing shaft is fixed on the loading plate. The reversing shafts are driven by the reversing motors to reverse the loading plate relative to the inner frame.