Objective: To explore the application effect of bedside ultrasound monitoring of diaphragmatic function on patients with mechanical ventilation during weaning. Methods: Sixty patients with mechanical ventilation in the hospital from January 2022 to December 2024 were enrolled as study subjects, and were divided into control group (n=30, using the current method of independent test to evaluate whether to remove the tube) and trial group (n=30, using the method of ultrasound monitoring to evaluate the diaphragmatic function of patients to guide whether to remove the tube). The diaphragm function [diaphragmatic excursion (DE), diaphragmatic thickening fraction (DTF)], monitoring indicators [respiratory rate (RR), heart rate (HR)], ventilator use time and extubation failure rate were recorded and compared between the two groups before spontaneous breathing test (SBT) and after 30 min of SBT. Results: Before SBT, the DE, DTF, RR and HR were close between groups (P>0.05). After 30 min of SBT, the DE and DTF in the two groups were enhanced compared with before SBT, and the DE and DTF in trial group were higher than those in control group (P<0.05). The RR and HR in the two groups were risen after 30 min of SBT than those before SBT, but the indicators in trial group were lower than those in control group (P<0.05). The ventilator use time was shorter in trial group than that in control group (P<0.05). The success rate of extubation in trial group was higher than that in control group by more than 5% (P<0.05). Conclusion: During weaning of patients with mechanical ventilation, bedside ultrasound monitoring of diaphragmatic function is helpful to enhance the success rate of weaning and shorten the use time of ventilator, and it has popularization and application value.