Aiming at the problems of greatly increasing the w(MgO) in the sinter, which may lead to an increase in the return rate of the sinter, and a decrease in the grade of raw materials into the furnace, a method for preparing magnesium pellets by adding MgO powder with a belt roaster is used to research the effects of different w(MgO) on the chemical composition, cold strength, metallurgical properties and high temperature consolidation characteristics of the pellets under the best thermal system and the best pellet size distribution. The results show that, with the increase of the w(MgO), the compressive strength of finished pellets obviously decreases, but its reduction degree increases, its reduction expansion rate decreases, the softening temperature range and the reflowing temperature range slightly increase. Under the thermal system of preheating time 6 min, preheating temperature 950 ℃, roasting time 9 min, roasting temperature 1170~1190 ℃, and further increase in the proportion of 10~12.5 mm granular pellets, the finished pellets with good metallurgical properties can be obtained. At the same time, the blast furnace runs stably and smoothly, and the economic and technical indicators of the blast furnace are significantly improved, in which, the coke ratio is decreased by 6.9 kg/t, the coal injection ratio is decreased by 2.2 kg/t, the coke nut ratio is decreased by 0.4 kg/t, and the total fuel ratio is decreased by 9.5 kg/t.