In recent years considerable attention is being paid to the blue-shift of photoluminescence due to quantum confinement in the nanostructure. By employing two simple models of one-dimensional crystal potential，we study the electronic energy spectra and confinement energies by solving the Schrdinger equation for the models. Based on the calculation of the confinement energies in the nanostructures，the size- and potential-dependence of the confinement energy and the blue shift are investigated. The results suggest that: with creasing size of the system the energy of electrons at the bottom of the conduction band decreases，but increases at the top of the valence band. Therefore，the confinement energies increased abruptly as the size of nano-particle (or nanostructures) decreases. Meanwhile，our results for the confinement energies show obvious difference from the ones calculated by the effective-mass approximation of ten used in the literature. Moreover，we also find that the band gap and blue shift depend on the crystal potential in the systems，and the confinement energies decrease as the potential increases.