Energy loss for high and low energy ions at the surface is reported from a theoretical point of view. The stopping powers of the high energy ions are expressed as a function of the distance s from the surface for single atomic-electron excitations, and bulk and surface plasmon excitations. We show that the stopping powers for low energy ions at the surface are calculated by two different methods, and are combined by a simple formula making use of the neutralization probability. The surface potentials excited by moving ions at the surface are also studied. The "skipping motion" and "standing up" effect are two typical examples for the ion trajectories near the surface.