Abstract: Based on the study of degree of liberation of different particle size and there separation results on electrostatic separator for candle coal mined from Shengmu and fat coal from Qinghai,the paper presents that for different coals,the degree is different under same particle size,the main reason of this difference due to the embed properties of mineral matter.The result of separation test made on electrostatic separator shows the satisfied result obtained when separation of 0.3～0.15mm and 0.05～0.074 mm size fraction materials with electric separator,that can effectively remove mineral matter from coal,so that it is significance for deep process of coal product.