In our previous work, graphene-supported Pd catalyst (Pd/rGO) exhibited higher activity and selectivity for the liquid phase selective hydrogenation of resorcinol to 1,3-cyclohexanedione compared with other catalysts. in the present study, further experimental and theoretical investigations were conducted to reveal the reaction mechanism and the catalytic mechanism of Pd/rGO for resorcinol hydrogenation. The effects of graphene nanosheet and the solvent on the reaction were investigated, and the pathway for resorcinol hydrogenation was proposed supported by density functional theory (DET) calculations. The results showed that the excellent selectivity of Pd/rGO to 1,3-cyclohexanedione was attributed to the strong pi-pi and p-pi interactions between the graphene nanosheet and the benzene ring as well as hydroxyl in resorcinol molecule, which was in agreement with our previous speculation. In weak polar aprotic solvents, solvation free energy had less impact to the pi-pi and p-pi interactions mentioned above. In strong polar aprotic solvents and polar protic solvents, however, the influence of solvation free energy was much greater, which led to the decrease in the conversion of resorcinol and the selectivity to 1,3-cydohexanedione. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.