Abstract：Objective：To observe the clinical efficacy of bowels-unblocking and lung-purging therapy combined with mechanical ventilation in treating moderate-to-severe acute respiratory distress syndrome （ARDS） with lung-heat and bowel-excess syndrome in children， and its effects on respiratory mechanics and hemodynamics. Methods： A total of 62 children with moderate-to-severe ARDS treated in the pediatric intensive care unit of Affiliated Hospital of Jining Medical University from June 2021 to June 2024 were divided into the control group and the observation group using the random number table method， with 31 cases in each group. Both groups received conventional treatment， with the control group receiving mechanical ventilation alone and the observation group receiving additional bowelsunblocking and lung-purging therapy （modified Da Chengqi Decoction）. The treatment course was five days for both groups. Clinical parameters including invasive mechanical ventilation time，non-invasive mechanical ventilation time， total ventilation time， total oxygen therapy time， hospital stay， mortality， and adverse reactions were recorded. Respiratory mechanics parameters [oxygenation index （OI），peak inspiratory pressure （PIP），positive end-expiratory pressure （PEEP）， and mean airway pressure （Pmean）]， hemodynamic parameters [mean arterial pressure （MAP）， central venous pressure （CVP），and heart rate （HR）]，and inflammatory markers [white blood cell count （WBC）， C-reactive protein （CRP）， and procalcitonin （PCT）] were compared before and after treatment. Results： After treatment， the observation group showed significantly shorter invasive mechanical ventilation time， non-invasive mechanical ventilation time， total ventilation time， total oxygen therapy time， and hospital stay compared to the control group （P＜0.05）. There was no significant difference in mortality between the two groups （P＞0.05）. Both groups showed significant improvements in respiratory mechanics parameters （OI，PIP，PEEP，and Pmean） compared to before treatment （P＜0.05）， with the observation group demonstrating lower parameters （P＜0.05）. CVP and HR decreased significantly in both groups （P＜0.05）， while MAP remained stable （P＞0.05）. There was no significant difference being found in the comparison of MAP，CV and HR between the two groups （P＞0.05）. The WBC，CRP， PCT in peripheral blood decreased significantly in both groups （P＜0.05），with the observation group showing greater reductions （P＜0.05）. No significant adverse reactions were observed during treatment. Conclusion：The combination of bowels-unblocking and lung-purging therapy and mechanical ventilation demonstrates significant efficacy in treating moderate-to-severe ARDS with lung-heat and bowel-excess syndrome in children. This integrated approach effectively improves oxygenation，reduces ventilator support parameters，shortens mechanical ventilation duration，decreases the levels of peripheral blood inflammation，and reduces hospital stay without significantly affecting hemodynamics.