Purpose: A systematic review of the literature on diagnostic and therapeutic indications, techniques, and complications of dacryoendoscopy (DE) was performed. Methods: The authors performed a PubMed search of articles published in English on DE. Data were collected and classified according to the categories of the disease. The clinical outcomes and limitations were particularly analyzed. Results: The lacrimal drainage system from the canaliculus to the inferior meatus could be examined based on the specific anatomical features by DE. The canalicular mucosa is smooth and brightly colored, the lacrimal sac shows covering mucosa with good vascularization and the nasolacrimal duct is lined with bright tubular mucosal folds. DE allows direct visualization of the detailed internal condition of the lacrimal disorders, to directly diagnose the site of obstruction with accuracy and address the causes and recanalize the lacrimal drainage system using assisted micro lacrimal surgical instruments in the tearing patients. Conclusions: Better visualization of the lacrimal canal with DE improves the understanding of physiology and precise identification of the obstructing lesions, both of which are the key to a comprehensive management for the tearing patients.