The invention provides a plasma waste gas treatment device and method, and belongs to the technical field of waste gas treatment.The plasma waste gas treatment device comprises a thermal reaction system, an air inlet system, a cooling system, a multistage purification washing system, an exhaust system and a liquid circulating system, and the structureis compact, safe and reliable.The plasma wastegas treatment method comprises the following steps of: carrying out high-temperature cracking reaction after waste gas to be treated enters into the thermal reaction system through the air inlet system, and carrying out quenching and preliminary purification after entering the cooling system; carrying out washing and purification for a plurality of times after entering the multistage washing system; finally discharging the waste gas from a chimney through a dehydration layer under the action of an induced draft fan.The waste gas is subjected to high-temperature cracking, cooling, preliminary purification and multistage purification, so that the purification speed is obviously improved; and the waste gas which can be treated by the method comprises perfluorides, inflammable substances, corrosion, poisons and the like, the purification is thorough, the method is safe and reliable.