With phenanthrene and hydrogen as raw materials, the hydrogenation of phenanthrene was tested over CoMo/Al2O3 catalyst in a fixed-bed microreactor. Effects of temperature, pressure and space velocity on the reactions were systematically investigated. On the basis of the equilibrium constants calculated by thermodynamic method and kinetic equation derived by the adsorption theory of Langmuir-Hinshelwood-Hougen-Watson, the rate constants, activation energy, and adsorption constants were estimated by the Broyden-Fletcher-Goldfarb-Shanno optimization method, and the different reaction networks were compared and screened. In this study, the result showed the path from 9,10-dihydrophenathrene to tetrahydrophenathrene could be neglected, and the path from 9,10-dihydrophenathrene to 1,10-octahydrophenanthrene could not be excluded.