The stopping power in heavy charged particles is an important parameter in determining the energy loss. In this paper we calculated the stopping power of proton in materials like Brass, Al, Cu, Pb, Water, Plexiglas, Galactic within an energy range 0.1 to 10 5 MeV. This is done through a Monte-Carlo method using an object oriented tool-kit i.e. GEANT4 which is developed for the virtual study of high energy particle physics. The results of the stopping power of proton and its applications are all discussed in detail. Keywords- Geant4, Software toolkit, Stopping power, Proton