The threshold current density, temperature dependence and gain spectra of InGaAs/AlGaAs single quantum well (SQW) laser grown by MOCVD were studied. A low threshold current density of 200 A/cm2 for a 2000 μm long stripe laser was achieved. The laser showed good thermal stability with a characteristic temperature T0 of 179 K. In low temperature region of 160～220 Κ the threshold current density of InGaAs/AlGaAs SQW laser decreased with temperature, indicating a negative characteristic temperature.