On the basis of the components of the raw feed, two basic conditions need be met to prepare super-low-ash coal: High-density components (+1.55 kg/L) need be preremoved, and the separation accuracy should not exceed 0.015. Two-stage equal-density dense medium cyclones were developed to improve the separation accuracy. The research was applied to commercial production in the Taixi coal preparation plant, where super-low-ash coal with A(d) (ash content) < 2.00% was prepared with good economic benefits. The actual industrial production results showed that the two-stage equal-density separation is advantageous to the production of super-low-ash coal. The separation accuracy (Ecart probability) reached 0.015, and the failure free operation time was more than 10000 h. As a result, the reliability and economic performance of industrial super-low-ash coal production are improved, which will further promote the development of coal-based materials.