Abstract: This paper described the three kinds of typical slime flotation processes including primary flotation,secondary flotation and re-flotation of tailings or middlings in secondary flotation,presents that based on the slime floatability test result,reasonable select and make the design ideas and methods for flotation technological process,and points out that due to the feed raw coal from different sources in large sized coal preparation plant,caused big difference in coal quality,so that should use the technological process which can make the primary flotation and secondary flotation flexible interconversion