The invention discloses a coal-fired boiler bypass flue wastewater evaporation device and technology.The device comprises a coal-fired boiler, an air preheater, a dust remover and a wastewater pump station.The dust remover is provided with an ash conveying pipeline and a follow-up flue.The air preheater is communicated with the dust remover through a dust removal flue, the coal-fired boiler is communicated with the air preheater through a denitration device, the denitration device is communicated with the air preheater through a preheating flue, the preheating flue is communicated with the dust removal flue through a bypass flue, an atomizing nozzle is arranged in the bypass flue, the bypass flue is provided with an additional dust remover, the additional dust remover is provided with an additional ash conveying pipeline, and a heat exchanger communicated with the wastewater pump station is arranged on the bypass flue or the preheating flue.The technology comprises preheating, atomizing, evaporating separation and capturing of solid pollutant.According to the coal-fired boiler bypass flue wastewater evaporation device and technology, existing equipment and flue gas heat are sufficiently utilized, moisture in wastewater is evaporated to be steam, pollutant in the wastewater is crystallized to be in a solid state, moisture and pollutant in the wastewater are completely separated, and therefore wastewater of the boiler is thoroughly and harmlessly treated.