The invention relates to a plasma and pulse discharge composite polishing device for a large-scale complicated metal surface. The plasma and pulse discharge composite polishing device for the large-scale complicated metal surface aims to solve the problems that according to a conventional metal surface precise polishing method, the polishing efficiency is low, machining stress is prone to generation, and the surface is prone to damage are solved. The plasma and pulse discharge composite polishing device comprises a radio frequency power supply, a radio frequency power supply adapter, a high-voltage direct-current pulse power supply, a pulse power supply polarity adjusting device, a high-voltage direct-current pulse power supply impedor, a plasma torch, a polishing protective cover, a control circuit and a linkage mechanism. According to the plasma and pulse discharge composite polishing device for the large-scale complicated metal surface, precise machining and polishing are conducted on the metal surface at the atmosphere pressure, a vacuum chamber and a special polishing solution are not needed, equipment cost can be reduced, the application range is widened, the machining efficiency is several times as high as that of a traditional polishing method, unstressed machining is conducted, surface damage and subsurface damage are avoided, surface pollution is avoided, and the surface roughness of a polished workpiece can reach Ra0.2 micrometer.