Hot electron relaxations in GaAs/AlGaAs multiple quantum wells were studied using photoluminescence excitation (PLE) spectroscopy. LO phonon emissions in the quantum wells were observed. A four band Kane model was built to calculate the deformation of sub valence bands due to the mixing effect of heavy and light hole bands. The deformation affects the measured PLE responses. The measured and calculated results show that photo excited electrons can cascade down to the exciton energy state directly by LO phonon emissions.