The Monte Carlo Antiferromagnetic Ising model was used to study the electrical properties and magnetoresistance of manganese oxides due to the charge ordering phase occurring at half doping, x = 0.5. The half-doped manganites have an insulator antiferromagnetic ground state. The internal energy, specific heat, resistivity, the magneto-resistance and magnetization have been investigated with different applied magnetic fields. Our simulation reveals that the resistivity decreases exponentially as the free charge increase to transport from the insulator to conductor phase. The magnetoresistance has positive high values with magnetic field. The obtained insulator–metal transition behavior candidates the half-doped manganites to be very good semiconductors diode junctions.