3-Mercaptopropyl Trimethoxysilane (MPTMS) is a common silane coupling agent and can fix ionic liquid on supporter in supported ionic liquid catalyst field. In this study, response surface methodology was used to design and optimize the reaction conditons which were MPTMS dosage, reaction time and temperature for the best MPTMS loading amount (S content). The optimum experimental conditions are MPTMS 1.43 g, time 31 h and temperature 391 K. The predicted S content is 0.95 mmol/g and the experimental is 0.91 mmol/g. The thickness of MPTMS layer is about 0.55 nm in SiO2 pore