To bury the substrate defects effectivel, the superlattice buffer layers are fabricated on the surface of the substrate, and a good interface can be gotten. It decreases the threshold current and increases the output power greatly. The quantum well lasers that we fabricated can be operated at room temperature, the wavelength is 778nm and the lowest threshold current at room temperature (CW) is 30 mA, the threshold current density is about 400～600 A/cm 2, the linear output power with uncoated facets is greater than 20 mW, and the width of the spectral line is 5 nm.