The rational utilization of Mongolian concentrate in the 624 m2 belt pellets of Baotou Steel is comprehensively investigated. The results showed that with the increase of the proportion of Mongolian concentrate, the grade of pellets improved, and the reduction expansion rate increased. When the ratio was less than 20%, the reduction expansion rate was less than 20.0%, mainly due to the precipitation of a large amount of metal iron in the pellet mineral composition after reduction. In the phase transformation of ferrite (FexO) to iron, iron whiskers growed outward from the surface of the float. The growth of iron whiskers caused the displacement or cracking of the grains, leading to the expansion of the pellet structure. The reduction expansion rate of pellets can be significantly reduced by adding an appropriate amount of silica. By adding an appropriate amount of silica, the reduction ratio of the pellets can be significantly reduced. When adding 30% to 50% of Mongolian concentrate, the reduction expansion rate of pellets can be reduced within 20% by adding 1.0% to 2.0% of silica. The quality of pellets met the requirements of blast furnace smelting production.