The invention discloses a hazardous waste incineration line flue gas purification treatment system, which comprises a quench tower, a cyclone dust collector, a dry deacidification tower, a filter bag, a wet washing tower, an alkali liquor neutralizing tower, a steam heater and a chimney. The outer wall of the quench tower is fixedly connected with a quench tower spray gun cooling water ring pipe, a quench tower spray gun compressed air ring pipe and a quench tower spray gun protection air ring pipe, the upper end of the quench tower is provided with a quench tower flue gas inlet, and the lower end of the quench tower is provided with a spray gun compressed air inlet pipe and a quench tower spray gun protection fan. According to the hazardous waste incineration line flue gas purification treatment system, the problem that flue gas purification treatment is not thorough is solved, the process is more reasonable, more convenient and more effective, the flue gas purification treatment effect is greatly improved, and finally the flue gas reaches the national flue gas emission standard, and after flue gas generated after incineration is purified by the flue gas treatment system, the concentration meets the emission requirement, and a better use prospect is brought.