The growth conditions for MBE-grown GaAs-GaxAl1-xAs DH lasers are reported which include the temperature-time cycles with a lower growth temperature, in-situ growth of ohmic contact electrode layer, and an annealing process after growth. The experiments indicate that the use of source materials with high purity, BN effusion cells, and the cryopump in the system play important roles in reducing the threshold current density of the lasers and improving their optical and electrical performance.