With the continuous development of critical care medicine, the survival rate of critical ill patients continues to increase. However, the residual dysfunction will have a far-reaching impact on the burden on patients, families, and health-care systems, and will significantly increase the demand of the follow-up rehabilitation treatment. Critical illness rehabilitation intervenes patients who are still in the intensive care unit (ICU). It can prevent complications, functional deterioration and dysfunction, improve functional activity and quality of life, shorten the time of mechanical ventilation, the length of ICU stay and hospital stay, and also reduce medical expenses. Experts at home and abroad believe that early rehabilitation of critical ill patients is safe and effective. So rehabilitation should be involved in critical ill patients as early as possible. However, the promotion of this model is still limited by the setting of safety parameters, the ICU culture, the lack of critical rehabilitation professionals, and the physiological and mental cognitive status of patients. Rehabilitation treatment in ICU is constantly being practiced at home and abroad.