Abstract: In order to expand the application of microwave technique in the refined processing of western coal resources with higher inertinite content, the formation rules of microwave-induced cracks were investigated with three kinds of typical higher inertinite content coal.The results manifested that the separate microwave irradiation has minor influence on the pulverizing characteristics of coal, but could further improve pulverization efficiency.Besides, it has different responses to coal samples with different particle sizes; the number of cracks and microwave energy are linearly increased; with the decrease of particle size, the number of cracks increases at first and then decreases, which reaches its maximum when the particle size varies from 74 μm to 125 μm.From the analysis of the morphology, growing and propagation of cracks by SEM and coal petrography slices, it can be known that higher inertinite content coal has three kinds of crack formation models under microwave induction, i.e., interface crack, in-maceral crack and differentiated crack.