Abstract: Recognizing a critical scenario and its etiology is the key point of the therapeutic direction. Critical ultrasonography is now more and more comprehensively used in monitoring organ function and predicting pathogenesis, and is recognized as a fundamental component of critical care. Respiratory and circulatory failure is the core part of a critical scenario, analysis of which is the advantage of critical ultrasonography. Furthermore, evaluation of the precursor disease is also of great significance, indicating the wide range application of critical ultrasonography.