To review the clinical, subclinical features and treatment outcomes of 10 adult patients with HLH treated in Department of Clinical Hematology, the No.108 Central Military Hospital from Jan. 2007 to March 2013. Patients and Methods: Retrospective researches on medical records. Diagnostic criteria were based on the International HLH Society in 1994 and revised in 2004 Results: The common clinical manifestations of HLH were long fever (9/10), anemia (9/10), and enlarged spleen (6/10). Subclinical features: 100 percent of patients were with Hemophagocytosis in bone marrow, meanwhile hypertriglyceridemia and hyperferritinemia (7/10), and neutropenia and thrombopenia (8/10). The mortality rate was 80 percent Conclusions: HLH is a rare but at a potentially fatal rate. Early diagnosis HLH includes gene diagnosis and timerly bone marrow transplatation follow by chemotherapy hopefully to rescue more patients.