Indium tin oxide(ITO) film is fabricated with vacuum electron-beam evaporation.A novel AlGaInP light-emitting diode (LED) with a 300 nm thickness transparent conducting indium tin oxide film as window layer is fabricated.LED chip was annealed rapidly in N2 atmosphere for 40 s .As the rapid thermal annealing (RTA) temperature increases,the luminous intensity increases at the beginning and then decreases while the voltage first decreases and then increases.And the optimal annealing temperature for the luminous intensity and voltage is 435 ℃.The result from Hall test of ITO film showed that the carrier concentration is the highest and the resistivity is the lowest when ITO is annealed in a RTA system at 435 ℃.The forward voltage of LED decreases due to the resistance of ITO and the Ohmic contact resistance decreased and the light output increases due to the better current-spreading effect of ITO as current-spreading layer