Abstract: To improve separation efficiency of magnetic separator,magnetic contrast tests was conducted for the feed and tailing of magnetic separator,which materials has different magnetic concentration,and magnetic contrast test also conducted for tailing of magnetic tailing that produced from dense medium solids contenting different content of magnetite. The tests results showed that,in the test range,when the magnetic material concentration of feeding between 180 g/L to 205 g/L,magnetic material recovery rate is the highest which is about 99. 80%; and the magnetite powder content is higher,the medium loss is lower. The result has certain guiding significance to improve magnetic separator feeding conditions,reasonable choice of magnetite powder and reduce medium consumption.