The invention belongs to the technical field of gas separation and water treatment, in particular to a device and method for acid gas concentration, desalination and separation after doctor solution regeneration. The device comprises a regeneration tower, a one-way gas valve, a water cooler, a knockout drum, a one-way liquid valve, a corrosion-resistant liquid pump, a reboiler, a compressor, a pressure control valve, a hydrate reaction unit, a stop valve, a slurry pump, a hydrate decomposition unit, a filter unit, a two-way liquid valve, an ice-making device, a grinding device, a water pump, a refrigerator and a hydrate and salt separation unit. Two hydrate reactors are adopted to respectively fix hydrogen sulfide or carbon dioxide released after the doctor solution regeneration, the enrichment concentrations of two gases are increased, the quality of subsequent sulphur preparation is improved, and cost is saved; by the utilization of the desalination effect in the hydrate forming process, thermal stable salts generated in the desulfuration and regeneration process of most of the doctor solution can be removed, loss of desulfurizer in the doctor solution is little, and most of the desulfurizer can be recycled.