In order to improve electrophoresis test for the undergraduate, the electrophoresis rates are measured and its potential values are calculated by methods of dialysis and complex for ferric hydroxide solvent respectively. The experiment results indicate that Potentials values are obtained between 43 ~ 48 mV after purification for the ferric hydroxide solvent by the dialysis method, which are more accurate and repeatable, potentials values are obtained between 32 ~ 47 mV after the complex method for the ferric hydroxide solvent with urea, this method is simple and also higher chance of success. It shows that the two methods on the experimental results have little difference. Therefore, the complex transacting with urea is more suitable for students.