Abstract: In order to solve the problems caused by the fine crystal particles，poor quality，more mixed surrounding rocks，low grade and complex and changeable ore properties in the ore of the third phase of Shirengou Iron Mine，the ore dressing workshop was studied by the comparing process tests. Three optimization and improvement measures were taken: ①controlling the feed rate of the ball mill，adjusting the overflow fineness of the classifier，and increasing the sand return ratio; ②adjusting the separation gap of the magnetic separator，cleaning the magnetic separator groove regularly，and improving the tailings rate of the roughing stage by about 3%; ③Replace the high frequency fine screen mesh，control the fineness of the product under the screen is about-0.074mm 64%.After optimization，not only the iron concentrate with a total iron grade of more than 68% was produced，but also the design capacity was achieved.

Key words: optional experiment, peripheral vein, grinding, magnetic separation