The invention discloses a wet desulfurization wastewater zero emission process and a device thereof; desulfurization wastewater behind a gypsum dewatering device is collected and enters a flocculation reactor, the desulfurization wastewater is softened, flocculated and clarified, and sludge is sent to a sludge processing device for dewatering; the clarified water after separation is desalted, the desalted water is reused in a desulfurization system, concentrated water is sent to an evaporation crystallization device, waste heat of a boiler flue gas is used for evaporation crystallization, and high-quality water steam is obtained after evaporation; an evaporated crystallized substance and the water steam are subjected to gas-solid separation, the high-quality water steam is sent into a desulfurization absorption tower for recycling, and the crystallized substance is discharged together with fly ash. The high-quality water steam can be completely recycled in the desulfurization adsorption tower; suspended solids, dissolved solids, heavy metals, high salt, and Ca<2+>, Mg<2+>, Cl<+> and F<-> ions and other substances are cured, separated and collected, the purpose of complete recycling of the desulfurization wastewater is achieved, and zero emissions of the desulfurization wastewater can be achieved. In addition, the method has no effect on other systems of a power plant, and has the advantages of high practicability, low investment, and wide popularization and use value.