Tricolor grating is a new type of spatial light modulator.In this paper,principle analysis shows that tricolor grating has the character of multi-wave superposed in spatial domain and separated in frequency domain.Its applications in the field of information technology are introduced,such as color photography,white-light color joint transform correlator,multichannel spectra photography,etc.It is point out that many other kinds of multicolor gratings can be fabricated from tricolor grating and will be applied further in the future.