Disclosed is a wheel milling window device, composed of a bottom plate, guide blocks, clamping slide blocks, mounting keys, hydraulic cylinders, hydraulic pipelines, connecting blocks, pressure claws, first rotating shafts, second rotating shafts, end face blocks, a mandrel, a mandrel seat, a locking jackscrew, a mandrel height adjusting post, a mandrel guide post, a mandrel guide post locking screw, a locking ring, circumferential positioning posts and circumferential slide blocks. The device can reduce the manufacturing cost, shorten the manufacturing period, effectively reduce the time for replacing a fixture and improve the efficiency of milling a wheel window.