In view of the significant differences in the reduction and expansion behavior of different types of pellets at various reduction temperatures,the effect of reduction temperature on the reduction and expansion properties of pellets is studied,a visualized horizontal resistance furnace is used to measure the reduction expansion rates of different types of pellets at temperatures ranging from 900 ℃ to 1 200 ℃ . The results indicate that during the reduction process,the reduction expansion rate of all types of pellets gradually increases,reaches a peak,and then decreases again. When it is reduced at temperatures ranging from 900 ℃ to 1 200 ℃ for 1 hour,the order of the maximum reduction expansion rate for the four types of pellets is as follows:ordinary alkaline pellets > magnesium-containing alkaline pellets > ordinary acidic pellets > low titanium acid pellets;however,as the reduction temperature gradually is increased from 900 ℃ to 1 200 ℃, the alkaline pellets undergo malignant expansion. At a reduction time of 41 minutes and a temperature of 1 105 ℃,the reduction expansion rate of ordinary alkaline pellets is reached to a maximum value of 98. 13%;at a reduction time of 37 minutes and a temperature of 1 082 ℃,the reduction expansion rate of magnesium-containing alkaline pellets is reached to a maximum value of 84. 10%. Under high-temperature reduction conditions,the alkaline pellets exhibit significant cracking and pulverization,with a large number of iron crystal whiskers and iron crystal grains forming on their outer surface. The results have certain guiding significance for understanding the actual reduction and expansion changes of different types of pellets under high temperature conditions in blast furnaces, and can provide a scientific basis for the research and production adjustment of high-ratio pellets ore smelt.