The impact of temperature on laser diode degradations were studied by equivalent circuit model simulation and accelerated degradation experiment. Two degradation modes of laser diode were analyzed and concluded that the active region degradation will cause the threshold current to increase, and the cavity surface degradation will cause the slope efficiency to decrease. The thermal characteristics of laser diode were modeled and simulated, and were concluded that the threshold current increases with the temperature rise. The accelerated degradation experiments were carried out by a laser diode accelerated degradation experiment platform. The results of simulation and experiment showed that the increase of temperature will aggravate the cavity surface degradation, but has no significant effect on the active region degradation of laser diode. These conclusions will improve the laser diode temperature degradation simulation modelling. The current study is beneficial for the mechanism of temperature on laser diode degradation and protective measures.