The clinical manifestations of lung infections in the elderly are characterized by the following three points: First, the incidence of lung infections in the elderly is particularly high. Older age, reduced respiratory capacity, lowered immunity and inadequate absorption of nutrients in the body can cause lung infections in the elderly, and they are often treated repeatedly or even hospitalized. Secondly, the clinical manifestations of lung infection are not typical. The symptoms of lung infection in the elderly are mostly poor mental health, unresponsiveness, weakness of limbs, rapid heartbeat, abdominal pain, diarrhea or nausea and vomiting, which are different from the symptoms of young people, so the infection is often ignored or misdiagnosed at the early stage. Third, there are more comorbidities, such as bronchitis, coronary heart disease, diabetes, reduced liver and kidney function and other diseases.