Graphene is a strictly two-dimensional material of carbon atoms, which has attracted considerable research attention since its discovery in2004. Apart from its many peculiar and interesting electronic properties, graphene is also regarded as a promising candidate for spintronic devices. A number of experimental studies of graphene have proven it to be a material possessing characteristics suitable for spintronic applications, such as the long spin relaxation length and the gate tunable room temperature spin transport. This thesis discusses a numerical study of the manipulation of electron spin in graphene with the help of exchange interaction induced by ferromagnetic proximity effect or spin orbit interaction （SOI）. It consists of the following seven chapters.Chapter one is an introduction to the research background. A brief introduction is given to the physical characteristics of mesoscopic systems, and we qualitatively characterize the quantum transport regimes. The electronic properties of graphene and its advantages for spintronic applications are briefly introduced. We also review the developments of spintronics, which helps us better understand the research background.In chapter two, we introduce the most popular theories for quantum transport. Scattering matrix, transfer matrix and Green’s function are all introduced with brief derivations, and the definitions and properties of these powerful approaches are also considered.In chapter three, we propose a method of generating spin currents in mono layer graphene through adiabatic quantum pumping by applying two periodic oscillating gate voltages to a monolayer graphene with exchange splitting induced by ferromagnetic proximity. The pumped charge and spin currents are sensitive functions of the Fermi energy and pure spin current and spin current with different degrees of polarization and large magnitudes are obtained in our scheme. We find that large spin currents can be obtained when the pumping amplitudes are increased for our spin-polarized pump.In chapter four, we study a method to generate pure spin current in monolayer graphene over a wide range of Fermi energy by adiabatic quantum pumping. The device consists of three gate electrodes and two ferromagnetic strips, which induce a spin-splitting in the graphene through the proximity effect. A pure spin current is generated by applying two periodic oscillating gate voltages. We find that the pumped pure spin current is a sensitive oscillatory function of the Fermi energy. Large spin currents can be found at Fermi energies where there are Fabry-Perot resonances in the barriers. Furthermore, we analyze the effects of the parameters of the system on the pumped currents.In chapter five, we studied spin-dependent transport in mono layer graphene with a spin-orbit barrier, a narrow strip in which the spin-orbit interaction is not zero. When the Fermi energy is between the two spin-split bands, the structure can be used to generate spin-polarized current. For a strong enough Rashba strength, a thick enough barrier or a low enough Fermi energy, highly spin-polarized current is generated （polarization-0.7-0.85）. Under these conditions, the spin direction of the transmitted electron is approximately perpendicular to the direction of motion.In chapter six, we investigate spin dependent transport in monolayer graphene with a spatial modulation of the Rashba spin orbit interaction （RSOI）. In this structure, spin polarized current can be generated with spin polarization being a sensitive oscillatory function of the Fermi energy. Rapid reversal of the spin polarization can be realized at some Fermi energies by slight changes in the Fermi energy. The magnitude of the spin polarization depends on the number of RSOI barriers.In chapter seven, we summarize the main results presented in this thesis and show our future work. We introduce our preliminary numerical results on the control of spins by Goos-Hanchen effect in the presence of double magnetic barriers. It is shown that an efficient spin beam splitter can be realized in graphene with double magnetic barriers.