The invention provides an end surface rigid-sealing cobwebbing tool and a machining method. The end surface rigid-sealing cobwebbing tool comprises a polishing blade, a cobwebbing milling blade and amilling cutter disc; a blade assembly groove is formed in a sidewall of the milling cutter disc; a blade assembly threaded hole and a blade deepness adjustment threaded hole are formed in the blade assembly groove; and the polishing blade and the cobwebbing milling blade are separately assembled on the blade assembly threaded hole and the blade deepness adjustment threaded hole through a compaction screw and a conical adjustment bolt. According to the end surface rigid-sealing cobwebbing tool, after a workpiece is coarsely machined, finish machining and cobwebbing machining can be finished inone step; besides, machining is not limited by the size of an end surface of the workpiece, namely, the tool can be larger than the surface of the workpiece and can also be smaller than the surface ofthe workpiece for machining; highest rotation speed is greater than 10000 rpm according to machine tool conditions; feeding speed can reach as high as 6000 mm/min; finish machining and cobwebbing machining of the end surface can be simultaneously finished with high efficiency and high quality; production cost is low; use is convenient; and the machining method has the features of being short in machining time, high in machining efficiency, high in machining quality and low in machining cost.