ObjectiveTo investigate the diagnostic significance of different pathology techniques (Immunohistochemistry and ISH)to detect EBV on bone marrow biopsy tissues of hemophagocytic syndrome. Methods Histological,immunohistochemicalandinsituhybridizationwereusedtostudythe hemophagocytic features and expression of LMP-1,EBER and other markers.Results25 out of 51 cases (49.0 ％)showed an active proliferation growth pattern while other 12 cases(23.5 ％)demonstrated a deterioration morphological character compared with their same age group. The left 14 cases (27.5 ％) showed a normal myeloproliferative pattern. 91.4 ％ (32/35) expressed CD68/KP-1 and 89.5 ％ (17/19) cases expressed CD68/PG-M1, which showed an abnormal increase of monocytes. 26 out of 51 cases (51.0 ％) were positive for EBER,while EBER and immunohistochemistry on LMP-1 were detected simultaneously in 41 cases.The EBER were positive in 19 cases(46.3 ％)but none for LMP-1(P =0.000).ConclusionHypoplasia or hemophagocytic features could be detected on bone marrow biopsy tissues of hemophagocytic syndrome, which might be slightly difficult to diagnose. So immunohistochemistry would be essential. Meanwhile, the detection of EBER is more helpful than LMP-1 for diagnosis.