The invention provides a device and method for reducing dioxin emission through smoke distribution, and belongs to the technical field of waste treatment. The device comprises a smoke distribution unit and a waste preheating unit. A baffle is arranged at the tail end of a distribution gas outlet pipe of the smoke distribution unit and divides an outlet of the distribution gas outlet pipe into an upper smoke distribution port and a lower smoke distribution port. The lower smoke distribution port is connected with the waste preheating unit. According to the method, smoke generated after waste incineration is distributed according to the particle content of the smoke, wherein the smoke with the particle content smaller than 20% is used for waste heat utilization, the smoke with the particle content greater than 80% exchanges heat with to-be-incinerated waste, and the to-be-incinerated smoke absorbs pollutants and particles in the smoke in the heat exchange process, so that the content ofthe particles and pollutants in the smoke generated after waste incineration is greatly decreased; and waste heat in the smoke is used, so that more energy is saved, and the environmental friendlinessis better.