This randomized controlled trial investigates the effects of prone positioning versus lateral positioning at different angles (30°, 90°, 120°) on pulmonary function improvement in patients with acute respiratory distress syndrome (ARDS). Utilizing electrical impedance tomography (EIT) technology, the study monitors key parameters including ventilation distribution and ventilation-perfusion matching in real time, while integrating respiratory mechanics and blood gas analysis data to comprehensively evaluate the therapeutic efficacy of positional adjustments. The study hypothesizes that high-angle lateral positioning may reduce adverse complications associated with prone positioning while effectively improving oxygenation and pulmonary function. The ultimate objective is to provide a safer and more personalized positional therapy regimen for clinical practice, optimizing ARDS treatment strategies to reduce mortality and enhance patient survival outcomes.