Copper electrowinning is an important extraction method in copper industry, which accounts a growing proportion of the world copper production. In copper electrowinning, not all the current is used for the deposition of Cu because of the existence of iron in the electrolyte. The reduction of ferric ions is the main factor to reduce the current efficiency. The current efficiency changes with the operating parameters such as electrolyte temperature, current density, iron concentration, copper concentration, etc. To obtain optimal operating conditions, thus reducing energy consumption, in this paper, a copper electrowinning current efficiency model was established with two methods of empirical formula and electrode kinetics. Electrochemistry, gas-liquid flow, transport phenomena and comparison to experimental data are considered for the accuracy of the model. The model can predict the current efficiency change with the above operating parameters, so as to provide valuable guidance for the optimization of process parameters.