The electronic structures of the strained superlattice (SLS) (InAs)1 (InP)1 (001)under two strain conditions (free-standing model and InP-substrate model) and the strained bulk materials corresponding to the molecular layers in the SLS as well as the unstrained bulk materials are calculated with the ab initio LMTO band structure method. The average bond energy of molecular layers in the two SLS are determined with the frozen-potential approach. The results show that the average bond energies are well aligned across the interfaces and this alignment is not almost affected by the condition of strain. Thus, the average bond energy can be considered as a very reasonable reference energy level for determined the valence band offset in SLS. The strain effects on the band structures of molecular layers in SLS and on the △Ev values are investigated. Results given by frozen potential approach and using Em as a reference level in this paper are in good agreement with the available experimental datum from XPS measurement.