The Lorentz force generated in the low-conduction fluid can be used to control the boundary layer effectively. In the present paper, experimental and numerical investigations have been performed to suppress the flow separation of a hydrofoil with a certain attack angle in the low-conduction fluid. Both experimental and numerical results show that the Lorentz force parallel to the moving fluid can suppress the flow separation and thus remove the von Karman street. However, when Lorentz forces are applied opposite to the moving fluid of the surface of the foil, the separation point cannot be suppressed, instead, it would move reversely to the leading edge and the vortex street of the downstream acts as in the cases with a large attack angle.