The preconditioning technique can address the stiffness of a low Mach number flow, while its stability is poor. Based on the conventional preconditioning method of Roe’s scheme, a low-diffusion scheme is proposed. An adjustable parameter is introduced to control numerical dissipation, especially over the dissipation in the boundary layer and extremely in a low speed region. Numerical simulations of the low Mach number and low Reynolds number flows past a cylinder and the low Mach number and high Reynolds number flows past NACA0012 and S809 airfoils are performed to validate the new scheme. Results of the three tests well agree with experimental data, showing the applicability of the proposed scheme to low Mach number flow simulations.