A new multi-color separation algorithm was proposed with example of CMYKOG six-colors printing system. The new algorithm ensures feasibility of multicolor separation by color subarea, and accuracy of the new color separation algorithm was improved by cell division. The workflow of the new algorithm is based on ICC color management mechanism, which includes two main parts, forward model and reverse color separation model. The forward model was used to calculate printing gamut. The reverse model was used for gamut mapping and color separation.