Abstract: Aiming at the requirements of color management, this paper presents a method for the formation, extraction and visualization of the biggest printer gamut. The method obtains the sampling of the biggest gamut through optimizing combinations of CMYK inks, builds its geometric model by convex hull algorithm, dissects the gamut described by geometric model, and visualizes the gamut or its section with the true color. The visualization software based on the above-mentioned technology was realized in MS Visual C++6.0 environment, which is an important aid in research of device color characteristics, color separation, and gamut mapping algorithms.