Abstract: In order to adapt to the changing situation of the coal market, the realization of -3mm following the depth of screening, improve the proportion of coal washing, optimize the structure of commercial coal, will Haerwusu coal preparation plant to carry out the research of banana screen transformation flipflow screen depth screening, and two sets of banana screen tested; test results show that the traditional banana screen will be transformed into relaxation the realization of 6mm depth screening, screening, increase the calorific value of commercial coal, improve the quality of coal production in 2; the current situation in the coal market, coal sales more space, to improve the economic efficiency of enterprises has obvious positive effect.