To prospectively evaluate the technical efficacy and safety of the double-lumen eustachian tube (ET) balloon catheter in patients with ET dysfunction. Patients who were diagnosed with ET dysfunction and needed balloon eustachian tuboplasty (BET) were prospectively enrolled. A double-lumen ET balloon catheter was used to dilate the ET and inject medicine. Efficacy results were assessed by the injection channel patency (ICP) rate, the injection reached the expected site (IRES) rate, and the improvement in eustachian tube function was evaluated by the seven-item Eustachian Tube Dysfunction Questionnaire (ETDQ-7) score. Safety results were assessed in terms of adverse events and device defects. BET was successfully attempted in 87 patients from April 2022 to August 2022 at two academic medical centers in China (01, 02). The ICP rate was 100%, and the IRES rate was 88.51%. The overall ETDQ-7 score was significantly reduced ( p < 0.001) postsurgically at both centers. There were no major complications or device defects. The double-lumen ET balloon catheter is technically effective and safe for the treatment of ET dysfunction.