Alkaline blackening solution, suitable for electroplating of red copper and high content of copper alloy. Used in combination with brass prepreg CWF-220 to produce a blackening layer and a film layer on the surface of a high zinc content copper alloy. It can form a black and bright copper oxide film on the surface of the workpiece. The blackness of the film exceeds the acid black film layer, and the adhesion of the film layer is good, no hanging ash, especially wear-resistant.