The invention provides a power source disc, and relates to the field of electric power detection auxiliary equipment. The power source disc comprises a bracket, a cable disc rotatably connected to thebracket, and a cable wound around the cable disc; the bracket is provided with a plugboard. The power source disc further comprises a rotary electrical joint, a stator of the rotary electrical jointis fixedly connected with the bracket, and a rotor of the rotary electrical joint is fixedly connected with the cable disc; and the stator is electrically connected with the plugboard, and the rotor is electrically connected with the cable. Power line twining of an instrument can be avoided when the power source disc is moved, continuous power supplying is achieved, and the detection working efficiency is improved.