In electrochemical machining (ECM) processes, flow field parameters are closely related to the distribution of machined product such as bubbles and Joule heat in the inter-electrode gap. Therefore, the flow field is usually regarded as the key factor for achieving better surface quality and machining efficiency during ECM processes. In this study, a multi-physics model combining the electric field, the two-phase flow field and temperature field was developed. The changes in the bubble volume fraction and the flow rate in the inter-electrode gap for different flow field parameters were simulated and analyzed by COMSOL simulation software. The results show that the flow rate increases significantly with increases in the inlet pressure. Changing the outlet cross-sectional area significantly impacts the bubble volume fraction and the flow rate of the machining area. After a certain proportion of the outlet cross-sectional area, the bubble volume fraction and the flow rate in the gap change significantly. In addition, increasing the static pressure is conducive to compressing the bubble volume in the machining gap. Experiments were also performed, and the results show that as the inlet pressure increases, the material removal rate (MRR)first increases and then tends to be stable. Reducing the outlet cross-sectional area can improve the MRR and surface quality, and the machining performance is the best when the outlet cross-sectional area is 50 degrees.