A power supply structure includes a main body and a plug. The main body has a circular containing space, a cylinder and a plurality of conducting plates. The cylinder has a retaining plane and at least one annular groove. The plug has a plug seat and a first cylinder. The first cylinder has a protrusion and at least one elastic device on an inner side of the bottom of the first cylinder. The elastic device has a resilient arm and a pressing member. The annular groove has a stop block and a fixing space. The protrusion is provided and placed into the annular groove, so that the plug can be fixed into the main body.