The present invention teaches a CF substrate, its manufacturing method, and a WOLED display device. The CF substrate includes a substrate, a pixel definition layer, and multiple filter patterns. The pixel definition layer has multiple openings, each corresponding to a sub-pixel area of the substrate. Each filter pattern is disposed on the substrate inside an opening of the pixel definition layer, and includes a quantum dot layer and a filter layer sequentially formed on the substrate. The CF substrate requires a single lithographic process to form the openings. The quantum dot layers and filter layers of the filter patterns are then formed by solution film formation in the openings, effectively simplifying the manufacturing process and enhancing the production efficiency. Applying the CF substrate to a WOLED display device also enhances the lighting efficiency, color gamut, and product quality of the WOLED display device.