Abstract: The coloration index Ra is one of the important aspects of evaluating performance of light source. A method of improving coloration index of white LED with complementary color is put forward. According to the calculated maximum of the coloration index, the main wavelength and light intensity of the complementary light can be confirmed. To make sure the possibility of this way, the complementary colour was carried out for a white LED called LE W E2A made in OSRAM. The result indicates that the coloration index of the LED is improved from 79.59 to 85.76 after adding the homogeneous light to one certain area, and the coloration index of compound light is improved to 93.01 after adding the homogeneous light to two claimed areas.