ICU patients are in a various of intense stress state due to their diseases and other factors. Analgesic and sedative treatments are routine used to control these adverse stress responses effectively. However, studies have shown that both over and lack of sedation can lead to many adverse outcomes, such as prolonged mechanical ventilation, ventilator-associated pneumonia (VAP), and increased delirium and mortality. Therefore, in addition to improved analgesic and sedative strategies, real-time and accurate assessment is important for analgesic and sedative management in ICU patients. Here, we review the characteristics of each analgesic and sedative assessments that widely used in clinic.