A green way was provided to produce lubricating ester oils under solvent-free conditions over an ionic liquid catalyst supported with mesoporous silica, which was prepared by using sol-gel method and exhibited high activity and selectivity for the esterification of pentaerythrotol with fatty acid at stoichiometric ratio to the corresponding pentaerythrotol tetra-esters. The catalyst was systematically characterized by TEM, TG/DTA, BET and FT-IR. Moreover, the stability of the catalyst was investigated, and it can be recycled for several times without significant deactivation.