The invention discloses a motor-driven flange end surface processing tool which comprises a fixing seat. A positioning clamping device, a rotating gear ring and a feeding gear ring are mounted on the fixing seat, the rotating gear ring is connected with a gear ring rotation driving device, a connecting seat which rotates along with the rotating gear ring is fixedly mounted on the rotating gear ring, a cutter radial propelling device is mounted on the connecting seat, a feeding power transmission is arranged between the cutter radial propelling device and the fixing seat, power of the feeding power transmission is converted into feeding power via the feeding gear ring, a cutting-feed adjusting device is mounted on the cutter radial propelling device, and a cutter is mounted on the cutting-feed adjusting device. The rotating gear ring drives the cutter to rotate, and power of the rotating gear ring is transmitted to the cutter radial propelling device via the feeding power transmission, so that the cutter is radially fed. The distance from the cutter to a workpiece can be adjusted via the cutting-feed adjusting device, so that the processing depth is controlled. The motor-driven flange end surface processing tool is simple in structure, wide in processing range, convenient to operate and low in manufacturing cost and is light, and the quality of flange end surfaces s processed by the tool meets national and international requirements on flange end surfaces.