850nm GaAlAs/GaAs multiple quantum well lasers are prepared by a domestic molecular beam epitaxy system.The lasers have threshold current density of 980 A/cm2 at room temperarure, The lasers stripe width of 8um, the lowest room temperature threshold current is 28 mA, a linear power output of 15mW, a differential quantum efficiency per facet of about 24%, and a weak temperature dependence of threshold current density (T0-361℃ in the range of -35℃ to +30℃) are achieved.