The judgment of left ventricular systolic dysfunction is of great significance for the diagnosis of heart disease, risk evaluation, and follow-ups of patients with heart disease. Evaluation of left ventricular systolic function is the most commonly used index in echocardiography. At present, the echocardiographic measurement of left ventricular function has changed from linear measurement and two-dimensional echocardiography to local and global strain analysis and three-dimensional echocardiography. Even if examination method is very superior and automatic, evaluating left ventricular systolic function is extremely challenging. This paper reviews the most widely used echocardiography, evaluates left ventricular systolic function in adults and children, and discusses its advantages, disadvantages and the research progress.