Based on the minimum wear rate theory, the coated carbide tools were used for dry turning the iron-based superalloy GH2132. The cutting parameters were optimized by the single factor test. On the minimum surface wear rate, the relation among the cutting force, cutting temperature, surface roughness and cutting parameters was researched. The phenomenon and tool wear mechanism were investigated by scanning electron microscope (SEM). It was shown that the lowest tool wear strength, the lowest tool consumption, the longest tool path, and the highest machining precision are obtained with feed rate f of 0.1 mm/r, cutting depth ap of 0.1 mm, and cutting speed v of 90 m/min. The tool wear mechanisms are the coating peeling off in the earlier stage and the chipping of cutting edge in the later period.