Structures were observed in the photoluminescence (PL) and the photoreflectance (PR) spectra of In x Ga 1 - x As/GaAs (x=0.1) strained-layer multiple quantum-wells (QWs) grown by molecular-beam epitaxy on GaAs (100)-oriented substrate. The properties of the ground state transitions and the excited state transitions are discussed. The band offset ratio Q c = 0.69 (Q v = 1 - Q c = 0.31) is given based on the analysis of PL, PR experimental results. An important evidence, which indicates that the light holes are confined in the GaAs layer forming a type II superlattice, is provided.