In the emergency and critical care medicine, infection is easy to merge to various basic conditions and diseases. In the social structure aging in critical care, the immune weakness was revealed as the result of severe infection and septic shock in the reduced function of neutrophils and lymphocytes. In the life-saving emergency care, cardiovascular diseases, diabetes, chronic renal failure and lever dysfunction are often observed, and the underlying diseases have the foundation of biological invasion after a first inflammatory attack of surgery, trauma, burn, and systemic injury. It will be placed into a susceptible situation such as artificial respiratory management. In this review, we discussed severe infection in emergency and critical care. It is necessary to pay attention to the drug resistance bacterias in own critical care setting by trends.