This article investigates the self-focusing effect of high-power laser beams in a nonlinear dielectric medium through mathematical modeling. The nonlinear Schrödinger equation (NLSE) was used as the core model and numerically solved in one-dimensional space using Python. Simulation results demonstrate that as the beam intensity increases, the self-focusing phenomenon becomes more pronounced. The findings are of practical importance in laser technology, optical fiber systems, and the control of high-energy pulses.