in this thesis,spin dependend transport and electron transport through of ng/sg(graphene/ superconductor graphen) are studied in the junction of ng/fgt/sg. due to andreev reflection conductance increases in the presence of superconductor graphene.also, by applying a voltage gate on a superconductor, fermi level shifts and the conductance is independent of ferromagnatic substrate. also, the conductance is controllable by voltage gate. the effect of physical parameters on conductance behaviour is studied. the presented results make possible to select proper parameters for designing an optimized system with the maximum transport. also, it has attempted that these proper parameters to be near the available values in lab. such a system can be used as a switching in electronic and spintronics nano devces.