Basing on the density functional theory and LMTO-ASA band method, we study the properties of an average hybridization energy Ez of sp3 hydrid orbital, near the interface in semiconductor superlattice. It is shown that the Ez can be considered as a reference energy level for calculating the valence-band offsets △Ev at heterojunctions. The results indicate that the theo-retical values of the △Ev obtained with this method for several hererojunctions are in agreement with other theoretical and experimental results.