The GaInP/AlGaInP heterostructure was grown on (100) GaAs substrate using low pressure metal-organic vapor phase epitaxy (LP MOVPE) . The growth temperature and pressure were held constant at 740 °C and 40 torr, respectively. The GalnP multiquantum well layers from 10 Å to 85 A were lattice matched to the substrate. High resolution transmission electron microscopy and low temperature photoluminescence measurements indicated that the GaInP/AlGaInP well layers were uniform in thickness and that the interface was abrupt and free of defects. For high performance of visible laser diodes, highly doped p-AlGaInP layer(8X1017/cm3) was obtained. It was also found that the Zn acceptor concentration increased with growth rate. In this study, the GaInP/AlGaInP laser diode, 645nm and 20mW, was fabricated by employing multiquantum well and highly doped p-cladding layer.