The zircons from Mingxi of Fujian Province assumes colorless, grayish brown and light blue after heat treatment. A process of heating and irradiation was designed to tackle them. The colors and their variations were studied by UV-NIR spectrometer. The formation mechanism of the zircon colors were discussed on the basis of experiments. It is shown that the brown color of the zircon is caused by color-center, and that the light blue color is attributed to Fe~(2+)Fe~(3+) intervalence charge transfer, which contributes to the beauty enhancement of the zircons.