A method and apparatus for direct drying of inorganic sludge with a drum drawing process, comprising the following steps: 1) drum mixed drying of slag and sludge: respectively conveying the slag and sludge into a drum (1) in proportion, completing mixing, heat exchange, dehydration, cooling and crushing of the slag and sludge under the rolling action of the drum (1) and a steel ball to achieve cooling, crushing and drying of the slag and sludge, and directly discharging the obtained mixture; 2) slag and sludge separation: separating the steel slag and dry sludge in a manner of combining screening and rotary separation; 3) tail gas treatment: treating dusts, sulfides and organic compounds in tail gas generated by the dry sludge by using wet alkali washing and activated carbon adsorption, and discharging the treated tail gas; and 4) tailing sludge treatment: generating steam and dusts in the drum treatment of the slag and sludge, allowing dusts to enter a tail gas treatment device (4) with steam, aggregating the dusts after wet washing or spraying, and then conveying into a tailing sludge blending device (5) by means of a conveying device, mixing and stirring the tailing sludge and original sludge, conveying the obtained mixture into the drum (1), and drying the mixture to realize zero discharge of undried sludge.