We demonstrate that a finite number of nano-slits can realize beam splitting and focusing of light by coating the metallic film surfaces with nonlinear Kerr medium. The numerical simulation shows that the beam splitting and focusing can be controlled by the incident light intensity. The splitting angle is quasi-periodically modulated by the incident light intensity, and the focusing length of forward propagating transmitted light decreases as the incident light intensity increases. These effects are explained by the surface plasmon polariton Bloch modes and self-focusing theory.