The grid-spacing dependency of the numerical solutions of the supersonic gas/particle impinging flow of the cold spray is investigated. The control parameters of the grid spacing in the nozzle are the radial grid spacing normal to the nozzle wall, the axial grid spacing at the nozzle exit, and the radial number of grids in the nozzle. The working gas is nitrogen with a pressure and a temperature of 2MPa and 600K at the stagnant chamber. The solid particle to be accelerated by the supersonic gas flow is spherical copper 5µm in diameter. The numerical results reveal that the computational result with coarsest grid poorly captures the supersonic gas flow in the nozzle. However, the impinging velocity of the particle onto the substrate differs less than 3.5% between those results obtained from the finest and coarsest grids.