Objective To explore the clinical effect, surgical methods and indications of contoured posterior semi-peripheral membrane of nasolacrimal duct in the treatment of benign maxillary sinus lesions.Methods Thirty patients with benign maxillary sinus lesions underwent routine preoperative rhinologic examination and sinus imaging examination. All patients underwent endoscopic surgery to enlarge the natural ostium of maxillary sinus. For easy entering the sinus cavity and removing lesion, the posterior half of the bony nasolacrimal duct and the attached mucosal tissue were removed to expand the natural ostium and retain the membranous nasolacrimal duct.Results Complete removal of lesion was achieved in all patients with proper protection of membranous nasolacrimal duct. Follow-up revealed well recovery with good epithelialization of the sinus cavity. Neither recurrence nor complications such as local numbness around the nose, nose collapse, epiphora occurred.Conclusion With advantages of expanding the surgical field and increasing the operating space via retaining the membranous nasolacrimal duct so as to reduce surgical damage, avoid complications and maximally preserve the physiological functions as well as prevent sinus stenosis, contoured nasolacrimal duct surgery is a surgical method worth promoting.