During the development of CED and its application, some problems have emerged in the parameters control of electrophoretic coating bath, because each enterprise has its own products and process condition. The parameters control of electrophoretic coating bath according to the principle of CED, the results of experiments and the actual circumstance of the CED enterprises were discussed. Some rational suggestions on the control of parameters, including solid content, conductivity,pH value, P / B ratio and cosolvent content were presented. Their influence on the manufacture of CED were discussed, which can provide lessons for enterprises of CED.