Background: Mechanical ventilation (MV) is required for most cases introduced the intensive care unit (ICU) as a portion of their process of care. However, either MV or the chronic illness can result in diaphragm dysfunction, an incident that may contribute to the incapability of MV separation to be done. Prolonged use of the ventilator significantly increases health-care expenses and subject morbidity and mortality. However, muscle disease symptoms and manifestations are frequently difficult to evaluate in a bedridden state ICU case due to complicating variables. A typical evaluation of diaphragm function lacks, non-invasive, time preservative, easy-to-perform bedside equipment or needs subject involvement. Lately, the utilization of ultrasound (US) has elevated a lot of interest as a simple, non-invasive approach for the assessment of diaphragmatic contractile activity. Objective: This narrative review aimed to briefly describe the common methods of diaphragmatic function assessment using ultrasound techniques. Methods: These databases were searched for articles published in English in 4 databases [PubMed - Egyptian Knowledge Bank - Google scholar- Science direct] and Boolean operators (AND, OR, NOT) had been used such as [Diaphragmatic AND Ultrasound OR Diaphragm function] and in peer-reviewed articles between 1985 and 2021. Conclusion: Diaphragmatic ultrasonography has been widely investigated and is still being explored as a predictor of effective mechanical ventilation weaning. Due to the substantial heterogeneity in research design and population, it remains difficult to draw general generalizations from individual studies. Even worse, terminology such as a failed breathing trial or unsuccessful extubation has not been defined across research, making comparisons of outcome measures unfeasible.