In order to widen the utilization way of air-granulated slag, they were used as a substitute for crushed stone to prepare ecological slope protection bricks. The effect of air-granulated slag on the properties of slope protection brick was investigated. The results showed that the strength of the sample prepared when no more than 46% of crushed stone is replaced with air-granulated slag was higher than that of the sample prepared without air-granulated slag. The strength of the sample increased gradually with the increase of the replacement amount of air-granulated slag. When the content of air-granulated slag was 40%, the compressive strength of the material was 31.03 MPa on the 3rd day, and 38.83 MPa on the 28th day. The freeze-thaw resistance grade of the prepared sample reached F150, and the autoclave stability was qualified. In addition, the leaching toxicity of the sample met the requirements of Identification standards for hazardous wastes-Identification for extraction toxicity (GB 5085.3—2007).