The invention discloses a respective-control phase change comprehensive waste heat utilization air preheating system and method. The system comprises an air preheater (33), an air preheater front air way (31), an air preheater rear flue (32), a condensate water main pipe (11), a steam main pipe (15), an air heater (28), a flue gas phase change cooler (12), a flue gas water cooler (7), a phase change water heater (17), a condensate water regulating valve (30), a steam flow regulating valve (14) and a liquid flow pipe (5). By means of the respective-control phase change comprehensive waste heat utilization air preheating system and method, a respective-control phase change heat exchange manner is adopted in a final-stage flue gas waste heat recovery heat exchanger, the final-stage flue gas waste heat recovery heat exchanger is combined with a condensate water air heater and a high-temperature flue gas cooler, and waste heat recovery benefits are improved.