We fabricate a GaAs-based InGaAs/InGaAsP multiple quantum wells (MQWs) laser at 1.55 μm. Using two-step growth method and thermal cyclic annealing, a thin low-temperature InP layer and a thick InP buffer layer are grown on GaAs substrates by low-pressure metal organic chemical vapor deposition technology. Then, high-quality MQWs laser structures are grown on the InP buffer layer. Under quasi-continuous wave (QCW) condition, a threshold current of 476 mA and slope efficiency of 0.15 mW/mA are achieved for a broad area device with 50 μm wide strip and 500 μm long cavity at room-temperature. The peak wavelength of emission spectrum is 1549.5 nm at 700 mA. The device is operating for more than 2000 h at room-temperature and 600 mA.