Many computational studies have been performed to examine the mechanism of methanol oxidation at various surfaces. In this work, the methanol decomposition mechanism on B11N11 and B14N14 nano-cages in gas and solvent phases by the DFT-D method has been performed. A complete evaluation of methanol decomposition was performed from five possible pathways, and kinetic and thermodynamic properties were investigated. Our calculations show that the initial scission of the O‒H bond in methanol decomposition, is the lowest energy barrier and the highest rate constant, and reaction proceeds via CH3OH → CH3O → CH2O → CHO→ CO. In general, Methanol oxidation is investigated on the B11N11 surface is more desirable. Remarkable differences in kinetic and thermodynamic result on methanol decomposition in B11N11 and B14N14 nano-cages indicate that the dehydrogenation of methanol might be structure-sensitive.