Voltage-current characteristics of GaAs-AlαGa1-αAs DH laser diodes have been measured at different temperatures in the range of 77-300K.Typical characteristics in the forward bias of many investigated diodes can be described by: I=I1+I2=1-s1,exp（AV）+Iexp（（p/nkT）V） where A and n are parameters Weakly dependent on temperature.