The invention discloses a novel process and device for treating carnallite, the device comprises a pulverized coal bunker, a conveying bunker, a gasification furnace, a melting furnace, a slag cooling tank and a slag lock hopper, the conveying bunker is located below the pulverized coal bunker, the melting furnace is located below the gasification furnace, the slag cooling tank is located below the melting furnace, the slag lock hopper is positioned below the slag cooling tank; the conveying bin is connected with the gasification furnace through a pipeline; the gasification furnace is provided with an inlet end and an outlet end, the inlet end of the gasification furnace is connected with a pipeline for conveying steam and oxygen, the pipeline for conveying the oxygen is provided with a heat exchanger, and the inlet end of the gasification furnace is also connected with a pipeline for conveying crude synthesis gas. The impurity-containing inorganic salt is solidified into the coal cinder, harmless treatment of the impurity-containing inorganic salt can be achieved, the solidification quality is stable, the problems of leakage, leaching and the like are avoided, the treatment cost is low, and obvious economic benefits are achieved.