The reported incidence of pleural effusion after percutaneous nephrolithotomy (PCNL) ranges from 2% to 16%, primarily attributed to pleural injury, extravasation of irrigation fluid, or absorption syndrome. Identified risk factors include renal pelvic pressure >40 cm H₂O during surgery, prolonged irrigation time, complex stones (multiple or large), supracostal access (particularly via the 11th or 12th intercostal space), medially or cranially located puncture sites, and a narrow costovertebral angle. Preventive strategies include maintaining low irrigation pressure (100-200 mmHg, equivalent to 136-270 cmH₂O), ensuring unobstructed outflow, selecting safer subcostal access routes (e.g., lateral to the scapular line, below the 10th rib), puncturing at end-expiration, intraoperative ultrasound guidance, and preoperative CT-based anatomical assessment. For treatment, conservative observation is appropriate for small effusions, moderate effusions may be managed by thoracentesis, and large or symptomatic effusions require closed thoracic drainage, with adjunctive human albumin administration if necessary to promote absorption.