A method of slicing and printing multi-color 3D object, the method comprising: a) loading a 3D data of a multi-color 3D object and reading coordinate information and a color information of the multi-color 3D object; b) executing a route slicing process according to the coordinate information to generate a plurality of object route data respectively corresponding to a plurality of object printing slices (30-38, 70-78), wherein each of the object route data records a layer number and respectively describes a printing route of the corresponding object printing slice (30-38, 70-78); c) executing an image slicing process according to the color information to generate a plurality of object images respectively corresponding to object printing slices (30-38, 70-78), wherein each of the object images records the layer number; d) generating a plurality of pollution-blocking route data respectively corresponding to a plurality of pollution-blocking printing slices (40-42, 80-82) according to the plurality of object route data, wherein each of the pollution-blocking route data records the layer number and respectively describes a printing route of the corresponding pollution-blocking printing slice (40-42, 80-82), the printing route described by each of the pollution-blocking route data is configured to partially overlap the printing route described by the object route data in the same layer; and e) controlling a modeling nozzle of a multi-color 3D printer to print along each of the printing routes respectively described by each of the plurality of the object route data for printing each of the object printing slices (30-38, 70-78) layer by layer, to print along each of the printing routes respectively described by the pollution-blocking route data in the same layer for printing each of the pollution-blocking printing slices (40-42, 80-82) used for blocking inks spraying down on the edge of the printed object printing slices (30-38, 70-78) when each of the object printing slices (30-38, 70-78) is printed completely, and controlling a coloring nozzle of the multi-color 3D printer to color the printed object printing slices (30-38, 70-78) according to the object image in the same layer when the pollution-blocking printing slices (40-42, 80-82) in the same layer is printed completely, wherein each of the pollution-blocking printing slices (40-42, 80-82) partially overlaps each of the object printing slices (30-38, 70-78) in the same layer. a) loading a 3D data of a multi-color 3D object and reading coordinate information and a color information of the multi-color 3D object; b) executing a route slicing process according to the coordinate information to generate a plurality of object route data respectively corresponding to a plurality of object printing slices (30-38, 70-78), wherein each of the object route data records a layer number and respectively describes a printing route of the corresponding object printing slice (30-38, 70-78); c) executing an image slicing process according to the color information to generate a plurality of object images respectively corresponding to object printing slices (30-38, 70-78), wherein each of the object images records the layer number; d) generating a plurality of pollution-blocking route data respectively corresponding to a plurality of pollution-blocking printing slices (40-42, 80-82) according to the plurality of object route data, wherein each of the pollution-blocking route data records the layer number and respectively describes a printing route of the corresponding pollution-blocking printing slice (40-42, 80-82), the printing route described by each of the pollution-blocking route data is configured to partially overlap the printing route described by the object route data in the same layer; and e) controlling a modeling nozzle of a multi-color 3D printer to print along each of the printing routes respectively described by each of the plurality of the object route data for printing each of the object printing slices (30-38, 70-78) layer by layer, to print along each of the printing routes respectively described by the pollution-blocking route data in the same layer for printing each of the pollution-blocking printing slices (40-42, 80-82) used for blocking inks spraying down on the edge of the printed object printing slices (30-38, 70-78) when each of the object printing slices (30-38, 70-78) is printed completely, and controlling a coloring nozzle of the multi-color 3D printer to color the printed object printing slices (30-38, 70-78) according to the object image in the same layer when the pollution-blocking printing slices (40-42, 80-82) in the same layer is printed completely, wherein each of the pollution-blocking printing slices (40-42, 80-82) partially overlaps each of the object printing slices (30-38, 70-78) in the same layer.