Amorphous ZrW2O8 powder and amorphous SiO2 powder were prepared by a sol-gel process as raw materials, and high-density ZrW2O8-SiO2 were successfully prepared at a much lower temperature of 923 K for a much shorter holding time of 10 min by spark plasma sintering (SPS) method rather than by conventional melt-quenching method. The relative densities of 0.85ZrW(2)O(8)-0.15SiO(2) and 0.70ZrW(2)O(8)-0.30SiO(2) were 99.4% and 96.6%, respectively. The combined technique of a sol-gel process and SPS should enable us to prepare the varied types of high-density composites of ZrW2O8 without severe thermal cracking caused by melt-quenching. The thermal expansion properties and dielectric properties of ZrW2O8-SiO2 were also investigated.