The invention discloses an industrial sludge, waste emulsion slag and metallurgical ash joint treatment system and a power generation process thereof, and belongs to the technical field of dangerous waste comprehensive treatment and heat energy utilization. The joint treatment system comprises a sludge feeding machine, a uniform stirring machine, a discharging machine, an air supply device, a coal mill, a blowing device, a coal-fired boiler, a steam turbine generator unit, a sludge and emulsion slag joint treatment machine and a dust removal device. The sludge and emulsion slag joint treatment machine is wholly of a horizontal bucket structure and comprises a drive shaft penetrating the center line of a bucket body, the two ends of the drive shaft are in transmission connection with an electric motor, the periphery of the drive shaft is fixedly connected with a scraper spiral stirrer, and a sludge inlet, a high-temperature smoke inlet, an emulsion slag inlet and a discharging outlet are formed in the bucket body. The problems that in the prior art, when industrial sludge, waste emulsion slag and metallurgical ash are independently treated, soil and water are polluted, bad smells are easily generated, treatment cost is high, and the boiler dust-containing waste smoke is low in treatment efficiency are solved.