The ternary system SiO2-P2O5-ZrO2 electrolyte and phosphotungstic acid (PWA) doped SiO2-P2O5-ZrO2 electrolyte were prepared for intermediate temperature fuel cell by using sol-gel technique. These silica-based proton conductors were confirmed to be non-crystalline structure without phase separation and good thermal stability by XRD and TG/DTA analysis. The doped PWA was found to be stabilized within the silica matrix and to enhance the proton conductivity. The proton conductivities of SiO2-P2O5-ZrO2 and SiO2-P2O5-ZrO2-PWA electrolytes showed 3.3×10^(-5) and 1.8×10^(-3) S/cm at 90 ℃, respectively, and the cell performance of SiO2-P2O5-ZrO2-PWA electrolyte was obtained as 0.02-0.25 mA/cm2 at 300 ℃ under humid condition.