The significance of wide color gamut image technology and the concepts of the visible color gamut, the conventional color gamut and the target color gamut of the mainstream wide color gamut video standards are scketched out. In view of the shortcomings of the RGB three-primary-color matching theory, the multi-primary-color wide color gamut technology is introduced. Then, the development of wide color gamut image technology is expounded, the existing extended color gamut technologies are classified, the current mainstream three-primary-color, multi-primary-color wide color gamut technology and their corresponding imaging and display devices are described. Finally, the difficulties and future trends of wide color gamut technology are discussed, which provide reference for relevant researchers to understand the wide color gamut video image technology.