The utility model provides a waste heat utilization system for waste incineration power plant, the waste heat utilization system includes msw incineration boiler, low pressure feed water heater, low -level (stack -gas) economizer, oxygen -eliminating device and water -feeding pump, the partly of msw incineration boiler exhaust flue gas gets into low -level (stack -gas) economizer heating comdenstion water, the comdenstion water comes from the superheated steam that the msw incineration boiler produced releases the water that condenses behind the released heat. According to the utility model discloses, heat recovery is carried out to the mode that adopts the low -level (stack -gas) economizer to add thermal coagulation knot water, carries out make full use of to boiler exhaust flue gas heat, solves the energy dissipation's that conventional msw incineration boiler exhaust gas temperature height caused problem.