Objective:To explore the effect of applying bed step training machine to carry out lower limb function exercise in the early lung rehabilitation activities of mechanical ventilation patients.Methods:The mechanical ventilation time of ≥24h, Acute Physiology and Chronic Health Score (APACHE-II) was selected from February 2019 to August 2019 in the Intensive Care Medicine Department of Shanxi Bethune Hospital, and 64 patients were selected with scores of ≥8 points, giving the step-stepping machine function exercise. Compared changes in heart rate, blood pressure, SpO 2 and ventilator support parameters before and after functional exercise (FiO 2, VT, Rate, PEEP, PS, oxygenation index, rapid shallow breath index). Results:The difference in heart rate, blood pressure, SpO 2 of patients before and after exercise of lower limb function was not statistically significant ( P>0.05). In the ventilator support parameters, FiO 2, VT, oxygenation index, rapid shallow breath index before exercise were (57.19±4.36) %, (421.22±17.31) ml, (172.75± 40.13) mmHg (1 mmHg=0.133 kPa), (47.28±3.89) times·min -1·L -1, after exercise were (49.67±5.82) %, (458.79±15.20) ml, (193.58±32.73) mmHg, (44.03±1.21) times·min -1·L -1, the difference was statistically significant ( t values were 1.389 -5.662, P <0.01 or 0.05).The difference of strain of rate, PEEP, and PS were not statistically significant ( P >0.05). Conclusions:Applying bed step training machine to carry out lower limb function exercise is an effective exercise method in the early Pulmonary Rehabilitation activities of mechanical ventilation patients. This method can make the oxygen concentration support parameters of the ventilator drop, the VT increases, increase patients' self-breathing, the oxygenation index increases, Rapid Shallow Breath Index decreases, and provides a prerequisite for shortening the mechanical ventilation time and going offline as soon as possible.