Pulmonary embolism and pulmonary congestion are two completely different diseases. Pulmonary embolism is mainly caused by the thrombosis of the venous vessels entering the pulmonary artery, thereby causing restricted blood flow in the pulmonary artery and leading to pulmonary embolism. Pulmonary congestion is often due to left heart failure, where the blood flow in the lungs cannot return to the left heart, causing the blood to be retained and congested in the lungs, forming this disease. However, they do have some similarities, such as presenting symptoms of difficulty breathing, shortness of breath, low blood pressure, shock, etc. But through diagnosis and additional examinations, these two diseases can be clearly differentiated. Therefore, careful differentiation is required in clinical practice because the treatments for the two diseases are completely different. If misdiagnosed, the treatment could be incorrect, leading to serious consequences from mistreatment.