Since the efficiency droop at the high current density of the InGaN-based light-emitting diodes (LEDs) influences the application of power-LEDs, the origin and the overcoming method of the efficiency droop have become a hotspot. Several possible mechanisms are discussed, such as Read-Shockley-Hall (RSH) recombination, Auger recombination, carrier localization, polarization field, efficiency of injected carries and heat effect. Some methods for overcoming efficiency droop are also discussed.