Studying 35 patients who have maxillary sinusitis were treated at Hospital of Thaibinh Medical University, the authors present the maxillary sinus puncture through uncinate process technique with 4 steps: local anesthesia, making a hole for drainage through uncinate process, washing maxillary sinus and removing the needle. The technique was endoscopic technique, minimal invasive, painless, and easy to be performed at hospital or otorhinolaryngology clinic.