High-density fuel was prepared by catalytic dimerization and subsequent hydrogenation. Different amounts of phosphotungstic acid (H3PW12O40, HPW) were loaded on mesoporous silica (SBA-15) by a simple impregnation method to prepare HPW/SBA-15 catalysts. The prepared catalysts were mesoporous. Characterizations indicated that the dispersion and the specific surface area depend on the HPW amount. The obtained dimers from catalytic dimerization of beta-pinene underwent isomerization and then dimerized to form the heterogeneous products. At the optimum load of HPW, the HPW/SBA-15 catalyst displayed the highest catalytic activity and the increased yield of dimer for a 3-h reaction. After the subsequent hydrogenation reaction, the obtained hydrogenated dimer products displayed a density and a volume calorific value comparable to those of commercial JP-10.