A new non-contact method is proposed to determine the forward voltage of LEDs.Firstly,the relationship between the forward voltage and the junction temperature is derived,and then the method to evaluate the junction temperature through the luminescence spectra is discussed,so that the relationship between the forward voltage and the luminescence spectra is finally obtained.The experimental results reveal that the estimated value of the forward voltage acceptably agrees with the actually measured value,which indicates that it is a good approach to achieve the relatively accurate forward voltage of LEDs through the luminescence spectra in the absence of direct measurement of the parameters,such as the junction temperature or the ideality factor.