The invention relates to a device and method for recovering hydrochloric acid from copper dross dechlorination tail gas, belonging to the technical field of tail gas treatment and hydrochloric acid recovery. A hydrochloric acid solution outlet in a hydrochloric acid absorption tower in the device is connected with a bottom inlet of a microwave heating furnace sequentially through an acid pump and a check valve; a tail gas outlet pipeline in the hydrochloric acid absorption tower is connected with the microwave heating furnace; the tail gas outlet pipeline is provided with a thermal-insulation layer; the center inside the microwave heating furnace is provided with an interlayer furnace pipe; the lower end of the microwave heating furnace is provided with a residual liquid outlet and a cooled tail gas outlet; the microwave heating furnace is provided with a liquidometer; a hydrochloric acid steam outlet on the top of the microwave heating furnace is connected with a condenser through a pipeline which is provided with a thermometer, a pressure meter and a safety valve; and an outlet of the condenser is connected with a regenerated acid tank through a vacuum pump. The copper dross dechlorination tail gas is introduced into the hydrochloric acid absorption tower, and introduced into the microwave heating furnace for regeneration to obtain the 15-25 wt% hydrochloric acid. The device has the advantages of simple structure and stable operation. The method has the advantages of simple principle and continuous process.