In order to improve the hydrophobicity of titanium alloy surface, the direct mapping relationship between contact angle and electrochemical machining process parameters was established by combining wetting theoretical model with multi physical field coupling simulation, and the effect of electrochemical machining with micro pit array mask on the hydrophobicity of titanium alloy surface was revealed. The theoretical model of surface hydrophobicity between the contact angle and the geometry size of micro pit array was established; the multi physical field coupling simulation of mask electrochemical machining was carried out; the direct mapping relationship between the contact angle and the process parameters was obtained by combining the theoretical model with the simulation results. In addition, with the surface contact angle as the dependent variable, the electrolyte mass fraction, mask size and electrolytic voltage as the independent variables, the orthogonal experimental simulation and calculation were carried out to obtain the best combination of process parameters and the experimental verification was carried out. The results show that, compared with the simulation calculation, the error values of diameter, spacing, depth and surface contact angle of the micro pit array measured by the experiment are 2.49%, 6.87%, 7.40% and 6.01% respectively, which indicates that the hydrophobic micro pit array surface with a contact angle of about 141° is successfully prepared without the modification of low surface energy materials.