Study of internal physical properties for hadrons (protons) is very important in physics. These properties are investigated by using different techniques. Elastic scattering experiments are one of them. Scattering theory using Quantum Electro-Dynamics (QED), is a suitable method especially for high energy experiments. Feynman diagrams are applied for Lepton-Hadron scattering to give a suitable expression for scattering cross-section known as Mott formula. In this thesis we drive it for electron-proton elastic scattering. A comparison between this prediction and experimental measurements is discussed. At low values of momentum transfer, the proton appears as a point- like particle while its constituents appear to be contributed to scattering process with high values. It concludes that there is a modified factor that must be added to Mott formula. This factor is related to electric and magnetic properties of the internal constituents of proton. These factors are called form factors. By comparison with experimental data, the calculated values agreed with that obtained from other groups. The charge radius of proton is expected to be 0.81 fm. Different images for proton are obtained due to different values of momentum transfer and compared with the photon wavelength.