Abstract: Ionic liquids have significant impact on dissolution and destruction of micro-structure of coal which has been widely applied in the field of coal chemical industry at present. We researched the impact of ionic liquids on micro structure and macro modification. The basic process of modification and inverting of coal were introduced in detail. In fact, the process of coal spontaneous combustion was the result of certain key functional groups reacting with oxygen. If these key functional groups were dissolved and destroyed by ionic liquids, it would inhibit and inert the coal spontaneous combustion. Then, we summarized the destruction and the difference of all kinds of ionic liquids on the main functional groups of coal molecule.