In this paper, we proposed the optimal process conditions on the electro-gilding process. The responses are plating thickness and Sn proportion. The factors are temperature, current density, and addition. We minimized the total number of experiments based on the principle of dividing into small part. We grouped the factors using the plating process information which we already knew. We did Hull Cell test to find relationship between plating solution and electric effects, and applied ANOVA and RSM to estimate the optimal process conditions.