Here we report a simple but effective approach to deposit graphene on silicon with dielectrophoresis. With a comb-shaped electrode design, graphene sheets can be captured between electrode pairs. The dielectrophoresis has proven effective in depositing a large-scale array of graphene sheets on desired locations. The dielectrophoretically deposited graphene demonstrates high sensitivity towards hydrogen ion concentration in an aqueous environment. The resistance of graphene is inversely proportional to the pH value of the solutions in the range of 5 to 9. The pH sensitivity of graphene is caused by the electrolyte-dependent gating effects and the creation of an electrical double layer at the liquid-graphene interface. The high-precision, high-yield dielectrophoretic deposition method provides an effective approach for large-scale fabrication and integration of future graphene-based nanoelectronic devices.