The coal mill is the key equipment of the coal milling and drying unit. Though the preliminary calculation on ZGM type coal mill,optimization on some parameters (raw coal particle, HGI, ash, air volume and air coal ratio) and some related apparatus (seal fan, wear resistant casing, coal chute, coal mill output, top separator, hydraulic oil and so on), some reference is provided for the equipment choose in the coal industry unit. The grinding output and primary air flow are the key parameters of the coal mill. Some the pipes and other equipments of coal mill should be optimized as actual need.