The invention discloses a complex feedforward control method for circulation and quenching of hazardous waste incineration flue gas. The complex feedforward control method comprises the specific control processes that (1) flow volume Q, temperature T, flue gas static pressure P and flue gas oxygen content of flue gas at a flue gas outlet of an auxiliary boiler are measured, and circulatory flue gas reflux temperature T1, quenched flue gas temperature T2, high temperature flue gas circular flow Q1 and quenched water flow m water are measured; (2) a pressure head of a high temperature circulating fan is controlled, the flue gas static pressure P is controlled to fluctuate in the range of +/- 100 Pa, and the volume percent of oxygen content is controlled to be 4% to 12%; and (3) a PLC controls a water volume controller to provide quenching water according to the measured quenched flue gas temperature T2 and the set quenched flue gas temperature. According to the method, working parameters like wind pressure state, the fan pressure head and system wind impedance in a flue gas flow body system are determined, circulatory flue gas flow control, flue gas division and flue gas quenching in a hazardous waste incineration system are effectively controlled, the stable operation requirement of the system is met, and energy conversation is achieved.