Abstract: The high temperature compressive strength of oxidized pellets in different atmospheres was tested by means of a self-made high-temperature compressive strength on-line test system.It is shown that the variation laws of high temperature compressive strength of ore pellets in neutral and oxidizing atmospheres are basically consistent.The strength of ore pellets increases with the increase of temperature below 800℃,but there is a significant decrease between 800℃ and 900℃.At the range from 900℃ to 1 100℃,the strength increases slightly with the increase of temperature.There is a sharp decline of strength above 1 100℃ and the strength nearly disappears at 1 200℃.As a whole the strength of ore pellets in neutral atmosphere is higher than that in oxidizing atmosphere.In reducing atmosphere,the strength of ore pellets decreases with the increase of temperature and reduction degree and almost disappears when the temperature reaches 1 100℃.The mechanism of the change in high temperature compressive strength of ore pellets was analyzed.