Reaction mechanisms of ethanol conversion to ethylene over H-ZSM-5, Cu-ZSM-5, Ag-ZSM-5, and Au-ZSM-5 catalysts were investigated using density functional theory calculations. Energetics, thermodynamic quantities, rate and equilibrium constants of ethanol conversion to ethylene were obtained using the B3LYP/LanL2DZ method. The catalytic abilities of these catalysts on the reaction rates of ethanol conversion to ethylene are in order: Au-ZSM-5 > > Ag-ZSM-5 > H-ZSM-5 > > Cu-ZSM-5.