A core wire polishing and grooving device comprises a device frame. The device frame comprises two supporting rods having the same height. The top of each supporting rod is provided with a welding rod driven bearing. A welding rod penetrates through the welding rod driven bearings. The exposed parts, at the two ends of the welding rod, of a core wire extend out of the corresponding welding rod driven bearings. A welding rod driving bearing is arranged between the two supporting rods. The welding rod penetrates through the center of the welding rod driving bearing. A welding rod motor can drive the welding rod to rotate through a welding rod transmission member. An abrasive disc is arranged at one end of the welding rod. An abrasive disc bearing is arranged at the center of the abrasive disc. An abrasive disc motor can drive the abrasive disc to rotate through an abrasive disc transmission member. Besides, the rotating direction of the abrasive disc is opposite to that of the welding rod. One supporting rod is provided with a hydraulic gas tank. The hydraulic gas tank is connected with a gun head through a hydraulic gas pipe. The gun head can spray flames used for grooving the core wire. The core wire polishing and grooving device can groove the polished core wire through flames, polishing and grooving of the core wire are completed on the same device, and the number of working procedures is reduced before the welding rod is used.