By solving Schrodinger equation and Poisson equation self-consistently, we have calculated the electronic structure for Si-doped GaAs/AlGaAs quantum well system at T=0 in the effective mass approximation. We studied the influence of the doping concentration and the thickness of the doping layer on the subband energies, eigen-envelope functions, Hartree potential, density distribution of the electrons, and the Fermi energy. It is found that at the given doping concentration, the subband energies decrease with the increase of the doping thickness, the width of the self consistent potential well increase, the deepth of the well decrease, the distribution of the electron density becomes wider, the peak value reduced. At the given thickness of the doping layer, with the increase of the doping concentration, the subband energies and Fermi energy monotonically increase, the self consistent potential well becomes narrower and deeper, the peak of the electron density distribution becomes higher, and concentrated around the center of the well.