Abstract: Objective:To investigate the clinical features of bone marrow infiltration in patients with malignant lympho -ma. Methods:Atotal of 133 patients with pathologically confirmed malignant lymphoma were collected and the characteris-tics of the bone marrow infiltration were analyzed. Results: The rate of bone marrow involvement was 21.8% (29/133 ). In 29 cases with bone marrow involvement, the ratio of patients with lymphosarcoma leukemia, bone marrow infiltration and lym-phoma cells less than 5% was31.0% (9/29), 55.2% (16/29) and 13.8% (4/29), respectively. In these 29cases, B-cell lym -phoma accounted for 55.2% (16/29), T / NK cell lymphoma accounted for 41.4% (12/29) and Hodgkin's disease accounted for 3.4% (1/29). The rate of bone marrow involvement in T / NK cell lymphoma was 37.5% (12/32), higher than that in B-cell lymphoma ( 18.2%,16/88). The difference between the two groups was statistically significant. Conclusion:There is a high proportion of bone marrow involvement in patients with malignant lymphoma, and distinct pathological types have different risks of bone marrow involvement. Overall, there is a higher rate of bone marrow involvement in T-cell lymphoma, mainly in lymphosarcoma leukemia. Bone marrow cytology is of great significance for patients with malignant lymphoma with regards to the correct staging, treatment options and prognosis.