In order to study the color characteristics of light-emitting diode, the characteristics of blue, green and white LED colors are analyzed. Firstly, the spectral power distribution of blue, green, white LED is respectively measured by using the monochromator, and then on the basis of the theory chroma, the main light source wavelength, color purity, color temperature and color rendering index are calculated. The results show that blue LED and green LED dominant wavelengths change little with different standard light sources, and the color purities are relatively high, at 0.64 and 0.87, respectively, the general color-rendering is very poor for the index of -29 and -14, so these blue and green LED are not suitable to be used as lighting source. White LED dominant wavelength largely change with different standard light sources, and color purity is relatively low, near 0, color rendering is good for the general color-rendering index of 82, so white LED is in full conformance with the lighting requirements.