For the color characterization of liquid crystal display (LCD), the spectral radiance curves are measured for EIZO CG 19 and NEC PA241 LCD monitors and the displayed colors are calculated based on spectral additive property. The results show that the spectral radiance curve of displayed color is the linear superposition of those of corresponding primaries, and there is a cubic polynomial relation between the digital driving value and the corresponding radiance of a single wavelength. A new color computation method is proposed. The computation accuracy of the proposed method is very high. It can be used for the color characterization of LCD.