Epstein-Barr (EB) virus, as a human host virus, lurks in the human body for a long time and can cause diseases when the body's immunity is low. This paper reports a case of EB virus pneumonia complicated with EB virus encephalitis in an adult patient admitted to a hospital. Fever was the main clinical manifestation, and the diagnosis was confirmed by metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) and cerebrospinal fluid, patient was completely improved after antiviral therapy.