Abstract: The grade and particle size of an iron ore are always operated manually.There are some problems in index adjustment,such as lag,poor accuracy and low stability.Combined with the next process pelletizing plant put forward the goal of 90% grade stability of iron concentrate and 95% particle size stability of concentrate,carried out the research on automatic adjustment of concentrate grade and particle size,and established three automatic control systems matching the grade of concentrate with the washing magnetic separator,the grade of concentrate with the high frequency vibrating screen,and the size of concentrate with the first and second section flow.The test results show that the grade stability of concentrate increases from 77.36% to 92.74% after manual operation by 15.38 percentage points.The stability rate of concentrate particle size increased from 83.15% to 96.83%,which increased by 13.68 percentage points,Achieved the expected target,met the pelletizing plant raw material demand.