It is a great challenge in catalysis to increase selectivity without sacrificing activity. Furthermore, the highly selective production of C-5-C-12 hydrocarbons, which are main components of gasoline fuel, from syngas is important for Fischer-Tropsch synthesis (FTS), particularly for its industrial process. Herein, we demonstrate an approach to increase selectivity for C-5-C-12 hydrocarbons, namely, the 145% increase in selectivity of C-5-C-12 hydrocarbons without sacrificing high CO conversion was obtained by tuning Al2O3 support with tungstophosphoric acid (HPW) for Ru-based catalysts. This finding offers a simple and novel approach to develop efficient catalysts for FTS.