ICUs mainly admit and treat life-threatening, various clinicopathophysiologic syndromes, including shock, severe infections, sepsis, acute renal failure, respiratory failure, and heart failure. Therefore, whether the infection will be transmitted in ICU is mainly determined by the condition of patients admitted to ICU.ICU can cause further spread of nosocomial infections, mainly due to the patient’s condition is very serious, a variety of infections, a variety of means of support, especially invasive means is particularly large, to a certain extent, ICU will cause the healthcare nosocomial infections cross-propagation. However, with the improvement of the level of nosocomial sensing technology, the increasing awareness of healthcare workers, the increase in hand hygiene compliance, and the implementation of various medical measures, nosocomial infections in ICUs have been greatly reduced. Currently, the main focus is on the occurrence of ventilator-associated pneumonia, as well as catheter-associated urinary tract infections and catheter-associated blood-borne infections.