Tool design in electrochemical machining is investigated including the effects of thermal-fluid properties of the electrolyte. A two-dimensional two-phase numerical model is used to predict the thermal-fluid field. Simulation indicates that, as the curvature of the electrode shape varies widely, the two-dimensional phenomenon of the flow is apparent and the two-dimensional model should be used during the numerical simulation. In addition, a higher electrolyte flow rate slightly reduces the two-dimensional effects. As the curvature of the electrode shape varies only slightly, one-dimensional analysis is accurate and capable of reducing the calculation time.