The invention relates to an N-vinyl pyrrolidone rectification reaction kettle which comprises a reaction kettle body. A combined heating system is arranged in the reaction kettle body and comprises heat exchangers, microwave irradiation heating devices, far infrared irradiation heating devices, filler metal wires, a transmission shaft, a rotating driving mechanism, temperature sensors, air pressure sensors and a control system. The N-vinyl pyrrolidone rectification reaction kettle is simple in structure, heating efficiency and heating temperature control accuracy of the reaction kettle can beeffectively improved while a heating temperature control range is expanded, and accordingly heating efficiency is effectively improved, and heating time is shortened; in addition, purity after N-vinylpyrrolidone rectification is remarkably improved, distillation residues resulted from self coagulation of N-vinyl pyrrolidone monomers are reduced, the occurrence rate of equipment faults including equipment blockage and the like caused by excessive residues and seriously affecting continuity and stability in rectification reaction is decreased, stability in equipment operation is improved, and equipment daily maintenance cost and labor intensity are reduced.