Abstract: According to the processing requirements of the complex three-dimensional micro-cavity in the processing of the diffused air film hole of the Inconel 718 aviation turbine blade, the micro-EDM milling process is adopted. The influence of key processes such asservo acceleration and deceleration control on the profile of the longitudinal and cross-section of the three-dimensional structure is studied. A general mathematical model of the bottom surface profile of EDM milling is established, and MATLAB is used to simulate and analyze the influence of different initial layer thicknesses on the bottom surface of the profile. he initial machining depth of 0.005 mm was obtained through experiments, and the longitudinal section of three-dimensional diffusion film hole with surface profile less than 0.01 mm was processed. Aiming at the 90° large turning angle existing in the transverse section of the three-dimensional structure, the hybrid S-type servo feed control strategy is adopted to reduce the concave transverse section caused by the excessive speed drop at the 90° turning angle, The transverse section of high precision diffusion film hole is obtained through experiments.