Abstract: Process and machine for multi-color injection molding of plastic products having three-dimensional appearance of continuous or discontinuous multi-color patterns according to a preset program through injection of various kinds and/or colors of resins into a cavity, the resins being injected from at least three injection units, merged into and blended together in a molten resin mixing manifold. The multi-color injection molding machine has more than three injection units established around the molten resin mixing manifold. The manifold internally holds an arranging chamber, which received a resin from each injection unit and forms a compounded or layered resin flow. For the purpose of presenting intricate multi-color patterns according to a preset program, the arranging chamber is detachably mounted in the molten resin mixing manifold.