Objective: To explore the clinical features, diagnostic methods and therapeutic strategy of silent sinus syndrome (SSS). Methods: A retrospective study was made on eight SSS patients treated during 2013-2016 in Longgang ENT Hospital and Otorhinolaryngology Hospital of the First Affiliated Hospital of SUN Yat-sen University. The following clinical data, including demographic data, symptoms, history of trauma and surgery, signs, imaging examination, endoscopic surgery and postoperative outcomes, were analyzed to summarize the diagnosis and treatment experiences. Results: Eight SSS patients showed the following clinical features: the proportions of both sexes and sinus sides were 4 to 4; seven cases (7/8) were adult, with an average of (48.1±11.8)y; seven cases (7/8) had long history of trauma or surgery, with an average of (17.9±10.5)y; seven cases (7/8) cannot recall the exact course of SSS; six cases (6/8) had no nasal symptoms; eight cases (8/8) had unilateral ocular discomforts; eight cases (8/8) had signs of unilateral enophthalmos (2-5 mm), accompanied with hypoglobus; and by CT and MRI scanning, eight cases (8/8) showed the unilateral maxillary sinus outlet obstruction, sinus full opacification, sinus wall bony rarefaction, sinus wall contraction, sinus volume loss, and the ipsilateral orbital floor bowing descent and orbital volume increase. After treated by endoscopic sinus surgery and followed-up for one year, four cases were cured, and the other four improved; no intra- or post-operative complications occurred; and no individual need a two-stage orbital plastic reconstruction. Conclusions: SSS often develops in the unilateral maxillary sinus of adult patient with long history of trauma or surgery, but the nasal symptoms and signs are silent. Diagnostic for SSS depends on characteristic ocular sign and sinus CT imaging. Endoscopic sinus surgery helps to improve ocular and nasal signs and promote orbital self-reconstruction.