850nm infrared light-emitting diodes (IR LEDs) composed of AlGaAs current spreading layers grown by multi-step variable growth rate method were investigated. It is found that the multi-step variable growth rate method can improve the surface morphology and the crystalline quality of the n-type Al0.25Ga0.75As current spreading layer and the epi-layers on top of it. Thus the leakage current and the series resistance of the 850nm IR LEDs can be reduced. Furthermore, the generation of non-radiative recombination centers within MQW active region can be avoided by using the multi-step variable growth rate method to grow n-type Al0.25Ga0.75As current spreading layer. Thus the light output power and the lifetime of the 850nm IR LEDs can also be increased.