This product is an electrolytic coloring additive of aluminum alloy anodizing nickel-tin salt system. By controlling the technological parameters, the aluminum alloy anodizing film can be a series of colors such as imitation stainless steel color, bronze color, champagne color, bronze color and black color. This product is composed of complexing agent, reducing agent, stabilizer and accelerator. It has the following characteristics: 1. Good complexing ability, strong anti-oxidation ability, effective prevention of stannous ion oxidation hydrolysis, reduce non-production consumption. 2. The bath liquid has stable performance, good dispersibility and good color uniformity and reproducibility. 3, the background color can be adjusted according to the customer's requirements, uniformity and coloring effect is better than the single tin salt, more easily out of true black. 4. The product is non toxic and does not pollute the environment.