Intensive care unit acquired weakness(ICU-AW)is common in clinical practice,especially muscle weakness and muscle dysfunction caused by delayed weaning from mechanical ventilation,which requires timely and effective imaging evaluation.Ultrasound,as a non-radiation,non-invasive,real-time and repeatable imaging technology,can serve as a preferred method for assessing muscle structure and function,and has important clinical value in the diagnosis and monitoring of ICU-AW.This review summarizes the clinical application and research progress of ultrasound examination in the non-invasive quantitative evaluation of ICU-AW.