Myocardial work (MW) is a new ultrasonic method to evaluate left ventricular systolic function by the integration of the whole left ventricular long axis strain and noninvasive left ventricular systolic blood pressure. MW can evaluate the left ventricular global and regional systolic function in the early stage of cardiovascular disease, follow up the progression and the prognosis of disease. This documentation aims to make echocardiographer better understand the concept, parameters, normal reference values and clinical application of MW are summarized as follows