AlGalnP/GalnP MQW samples of different numbers of wells were grown by LP-MOCVD and their Raman spectra were measured. Because of the doped current spreading layer, Ohm touching layer, top confining layer and bottom confining layer, coupled elec-tron(hole) -plasmon-LO-phonon modes are observed in Raman spectra. According to the Raman selection rule and the PL measurement, it is reasonable to evaluate the quality of AlGalnP/GalnP MQW by analyzing the relative intensity ratio of A1P-LO/TO.