The invention discloses a connecting device for an aerated concrete block and a steel column. The device can effectively eliminate cracks easy to occur at connection portions of the aerated concrete block and the steel column after a long time, avoids leakage of an outer wall and is durable in use and structure. The connecting device is formed by thread rolling round steel, a nut, adhesives and the aerated concrete block with holes. After the thread rolling round steel is welded with the steel column, the adhesives are coated on the brickwork head seam position, and the thread rolling round steel on the steel column penetrates the brickwork fast and then is fixed through the nut so that the brickwork is integrated with the steel column. The construction process is simple, high in safety and remarkable in durable effect.