Objective To construct an early activity program for children with mechanical ventilation,and to explore the safety and efficacy of its clinical application. Methods On the basis of literature analysis,the early activity program was constructed. The convenience sampling method was used to select 50 cases of 3~14-year-old children with mechanical ventilation into an experimental group from December 2020 to July 2021 at the pediatric intensive care unit（PICU） of a tertiary children’s hospital in Hunan province. A nurse-led early activity program was implemented on the basis of the routine nursing. 50 children admitted from April 2020 to November 2020 were selected into a control group,and the routine nursing was given. The heart rate,respiration,systolic blood pressure and oxygen saturation of the experimental group were collected 5 mins before the activity,at the 15th min of the activity and 5 mins after the activity,as well as the occurrence of adverse events such as unplanned extubation,falling and bed falling during the activity. Meanwhile,the completion rate of the early activity program was calculated to evaluate the safety and feasibility of the early activity. Muscle strength level,incidence of delirium,duration of mechanical ventilation and duration of PICU were compared between the 2 groups on day 1,day 3 and day 6,and the effect of the early activity program was evaluated. Results There were no statistically significant differences in heart rate,respiration and blood oxygen saturation of the experimental groups at 5 mins before the activity,at the 15th min of the activity and 5 mins after the activity（P>0.05）,while there were statistically significant differences in systolic blood pressure（P<0.001）. There were no unplanned extubation,fall and bed falling during the activity. The overall completion rate of the early activity program was 86.96%. There was no significant difference in muscle strength between the 2 groups on day 1 and day 3 （P>0.05）,and the muscle strength of the experimental group was higher than that of the control group on day 6（P<0.001）. The incidence of delirium in the experimental group was lower than that in the control group,and the time of mechanical ventilation and PICU stay were both shorter than that in the control group,with statistically significant differences（P<0.05）. Conclusion The early activity program for children with mechanical ventilation is safe and feasible,which can improve the muscle strength level of children,reduce the incidence of delirium,shorten the time of mechanical ventilation and PICU stay,and contribute to the early recovery of children.