To investigate the effect of AutoFlow on airway pressure and hemodynamics in mechanical ventilation constant volume-control ventilation mode, 100 patients receiving mechanical ventilation were randomly divided into observation group (SIMV-PSV-PEEP + AutoFlow) and control group (SIMV-PSV-PEEP). The results showed that the peak airway pressure and average airway pressure decreased with different flow rate settings and automatic flow conversion ( P < 0.05 ). The peak airway pressure and mean airway pressure decreased with different resistance settings ( P < 0.05 ). With different compliance settings, the peak airway pressure and average airway pressure decreased after being assisted with an automatic converter ( P < 0.05 ). Adding AutoFlow on the basis of SIMV-PSV mode can significantly reduce peak inspiratory pressure (PIP), mean airway pressure (Pmean), and airway resistance (R). There was no significant difference in hemodynamic monitoring results between the observation group and the control group. It is proved that the SIMV constant volume-controlled ventilation mode combined with AutoFlow can not only ensure tidal volume but also avoid excessive airway pressure, which has little effect on hemodynamics.