Objective:To investigate the clinical characteristics and therapeutic effect of adult primary hemophagocytic syndrome (HPS).Methods:The clinical data of a patient with primary HPS in the Third Affiliated Hospital of Southern Medical University in July 2017 were retrospectively analyzed, and the related literature was reviewed.Results:The patient was a 53-year-old female without history of basic disease, presenting as repeated high fever, with mutation of STXBP2 (FHL5), and was diagnosed as HPS according to hemophagocytic lymphohistiocytosis (HLH)-2004 criteria. The patient was treated with HLH-2004 regimen, and the efficacy was good. The patient was followed up until May 2021, and the overall survival time was 45 months.Conclusions:The atypical primary HPS and delayed primary HPS are rare, with mild clinical symptoms and only manifested by repeated high fever. Therefore, the gene mutations associated with HPS should be detected as soon as possible to confirm the diagnosis and to treat the disease early.