In this article, the mechanism of quick coal liquefaction at high temperatures is investigated theoretically and experimentally. Based on the bond energy of some model compounds in the coal molecular, it is pointed out that the bridge bonds of coal molecular structure during quick coal liquefaction at high temperatures can be broken. Taking Yanzhou bituminous coal as the research object, pyrolytic behavior of coal molecular and the mechanism of hydrogen-donor of quick coal liquefaction at high temperatures are studied. The reaction mechanism of quick coal liquefaction at high temperatures has been proposed.