Abstract: The tooth rings of the mine toothed-roll crusher currently produced by domestic manufactures are observed to have cracking problems in their manufacturing process. To address this issue, a study is made on brittleness of the heat-treated tooth ring. Under the prerequisite of allowing the overall hardness and toughness of the ring to remain unchanged, it is proposed to adjust the ranges of contents of elements while retaining the tempering brittleness features of the first-type heat-treated medium carbon alloy steel, and determine the optimal quenching temperature and low-temperature tempering temperature of the casting, through repeated experiments, so as to eliminate the cracking defects the ring in its manufacturing process, reduce its production and improve it's overall working stability.