Abstract: Measurements of Optical Absorption (OA) and Photoluminescence (PL) have been carried out on type I Multiple Quantum Well (MQW) system of GaAs-AlGaAs grown by Molecular Beam Epitaxy (MBE). An attempt has been made to compare exciton peak obtained for both heavy hole and light hole at band offset of 70/30 at different temperatures (Theory and Experiment). It is revealed from the investigation that the confinement energies of the particles increase with increase in the height of the potential barrier fro electron and decrease with increase in height of the potential barrier for light hole and heavy hole. The increase is more pronounced in the case of the light hole.