Some options of approximating the light-emitting diodes (LED) spectrums of radiation by various mathematical functions have been considered. On the example of red luminescence LED it has been shown that at the approximation of the LED spectrums by symmetric functions - the Gaussian function and parabola - there is a considerable error of shift of radiation wave central length, caused by asymmetry of the LED real spectrums. The general mean square error of approximation and the error in determining the radiation wave central length and the width of the LED radiation spectrum can be several times decreased at the approximation of the LED spectrum by the sum of two Gaussian functions.