The invention discloses a low-resistance spherical metal powder for cold spraying, and a preparation method of the spherical metal powder. The method comprises the steps of firstly, preparing spherical metal powder having the particle size within the range of 4-45 microns by an inert gas atomization method; enabling the prepared spherical metal powder to repeatedly impact on a matrix which has the corresponding specification and a convex surface at a high speed to form a pit on the surface of the spherical metal powder; classifying the treated spherical metal powder by airflow to obtain the spherical metal powder with the pit on the surface. The method is capable of effectively inhibiting the flow separation and accelerating the flight speed of the powder in the spraying process by improving the surface topography of the powder, thus improving the compactness of the coating.