<p>This paper conducts a comprehensive investigation into the electrochemical discharge machining (ECDM) mechanism, aiming to mitigate the susceptibility of thermal barrier coatings to cracking, delamination, microcracks, and the formation of recast layers during the precision machining of film cooling holes. Utilizing NaOH as the working fluid and optimizing chip removal through electrode rotation, this study systematically examines the machining state transition phenomena, material removal mechanisms, and the post-processing surface integrity of workpieces in the ECDM of film cooling holes with thermal barrier coatings. The findings reveal that during the ECDM process of the ceramic layer, only the electrochemical discharge effect remains dominant, with material removal being primarily driven by rapid thermal cycling and electrochemical discharge phenomena. Conversely, in the case of metal substrates, both electrochemical and electrical discharge machining are observed, with the material removal process involving a combination of electrochemical reactions and thermal effects. This research offers critical insights that could facilitate the efficient and high-precision manufacturing of film cooling holes embedded with thermal barrier coatings.</p>