Abstarct: In this dissertation, electronic, optical and magnetic properties of nanostructures baxsed on III-V group semiconductors have been studied by some computational methods. This investigation haven been done by Monte Carlo method, hybrid genetic algorithm-Monte Carlo-variational method, biased genetic algorithm-Monte Carlo-variational method (combination with extrapolation method), finite difference method, transfer matrix method, quantum transmitting boundary method, temperature dependent spin density functional theory and self consistent six band K.P method. In chapters two and three of this thesis, the algorithm of the hybrid methods have been described. In the chapter four, optical properties of GaAl0.7As0.3/GaAs and GaN/AlN multiple quantum wells with constant total effective length have been investigated by means of the compact density matrix method. The effect of the magnetic field on optical properties and oscillator strength of these systems were also studied. In the chapter five, miniband formation procedure for constant total length GaN/AlN superlattices have been investigated by using of the finite difference and transfer matrix methods. Then, spin up and down transmission coefficients and spin polarization of the GaAl0.7As0.3/GaAs multiple quantum wells in the presence of the Dresselhaus spin orbit interaction have also been calculated. In the chapter six, the behavior of a two dimensional electron gas confined within GaAl0.7As0.3/GaAs multiple quantum wells have been studied. Moreover In this chapter spin polarization of a two dimensional hole gas confined within GaAl0.7As0.3/GaAs/GaMnAs quantum wells has also been investigated by means of a self consistent six band K.P method.