Abstarct: The investigation of electron transport at the presence of intense electric fields in the semiconductor devices has always an interested issue for researchers and optoelectronic industries. In this thesis we used the Monte Carlo simulation method to investigate the steady state and transient case of electron transport (semi classical) in group III-V compound semiconductors. We also developed our model in order to simulate electron transport properties inside a ballistic diode. This model includes three sets of non-parabolic conduction band valleys which can be occupied by electrons due to high electric field. The effects of impurities and the acoustic phonon scattering, polar-optical and non-polar optical mechanisms have been considered. The dependence of temperature variations on the electron transport was also discussed.