Mesoporous silica supported Cs_(2.5)H_(0.5)PW_(12)O_(40) catalysts were prepared by impregnation method,and several silica supports with different pore size were utilized.N_2 adsorption,XRD and ICP-AES techniques were utilized to characterize the silica supports and catalysts.XRD results showed that the dispersion of Cs_(2.5)H_(0.5)PW_(12) was better for the silica support with larger pore size.The catalytic activity results showed that the pore size played important role on the catalyst activity and the molecular weight of PTHF. When Cs_(2.5)H_(0.5)PW_(12)O_(40) was dispersed on larger pore size silica support,the catalysts showed good performances for the synthesis of PTHF.The molecular weight of PTHF product on the sample in which Cs_(2.5)H_(0.5)PW_(12)O_(40) was dispersed on larger pore support was higher than that on the catalyst with smaller pore support.The leaching amounts of the active components for the supported Cs_(2.5)H_(0.5)PW_(12)O_(40) catalysts were much lower.After five reaction cycles,there were still good activities and stabilities for the supported Cs_(2.5)H_(0.5)PW_(12)O_(40) catalysts with larger pore silica supports.These results were much better than those of the supported heteropolyacid H_3PW_(12)O_(40) catalyst. Mesoporous silica supported Cs_ (2.5) H_ (0.5) PW_ (12) O_ (40) catalysts were prepared by impregnation method, and several silica supports with different pore size were utilized. N_2 adsorption, XRD and ICP-AES techniques were utilized to characterize the silica supports and catalysts. XRD results showed that the dispersion of Cs_ (2.5) H_ (0.5) PW_ (12) was better for the silica support with larger pore size. catalytic activity results showed that the pore size played important role on the catalyst activity and the molecular weight of PTHF. When Cs_ (2.5) H_ (0.5) PW_ (12) O_ (40) was dispersed on larger pore size silica support, the catalysts showed good performances for the synthesis of PTHF. PTHF product on the sample in which Cs_ (2.5) H_ (0.5) PW_ (12) O_ (40) was dispersed on larger pore support was higher than that on the catalyst with smaller pore support. The leaching amounts of the active components for the supported Cs_ (2.5) H_ (0.5) PW_ (12) O_ (40) catalysts were much lower.After fi ve reaction cycles, there were still good activities and stabilities for the supported Cs_ (2.5) H_ (0.5) PW_ (12) O_ (40) catalysts with larger pore silica supports.These results were much better than those of the supported heteropolyacid H_3PW_ 12) O_ (40) catalyst.