A new method of determining the junction temperature of GaN-based blue light em itting diode (LED) based on the double spectral parameters is developed.The GaN-based blue LED spectral distributio ns with di fferent ambient temperatures and pulsed currents are measured with spectrometer.Regardless of the heat induc ed by the pulsed current firstly, the relationships among drive current,centroid wavelength,full width at half m aximum (FWHM) and junction temperature are obtained.And then combined with the spectral distribution in th e real operating conditions,the drive current and the LED junction temperature are evaluated.The pulsed current -junction temperature compensation factor of the blue LEDs can be obtained by statistic analysis,whic h is used to improve the junction temperature on accuracy for the heat induced by pulsed current is cons idered.The results indicate that the pulsed current-junction temperature compensation factor is nearly constant for different types of GaN-based LEDs,which is 5℃/A with the rated power of 1W and the pulse width of 2ms.C ompared with the forward voltage method,the average error of the junction temperature determined by LED spectral distribution is about 2℃.Therefore,the spectral distribution method can determine the junction tem perature of GaN-based blue LED accurately.