Abstract: A flue gas purification system for hazardous waste incineration and a purification method are provided. The flue gas purification system includes a cooling deacidification coupling device. The cooling deacidification coupling device includes a reaction tower. A top of the reaction tower is installed with a spraying device, an inlet end of the spraying device is connected to a first liquid inlet pipe and a second liquid inlet pipe, the first liquid inlet pipe and the second liquid inlet pipe are configured to transmit a cooling substance and a deacidification substance. The reaction tower is connected to a gas inlet pipe and a gas outlet pipe. A bottom of the reaction tower is connected to an output pipe configured to output substances generated in the reaction tower. The spraying device is configured to mix the cooling substance and the deacidification substance with the flue gas.