Objective:To observe and analyze the morphological characteristic of bone marrow and peripheral blood in patients diagnosed with de novo acute leukemia.Methods:From October 1, 2015 to December 31, 2021, 1151 patients aged 47 (26, 62) years, consisting of 602 males and 549 females with newly diagnosed acute leukemia in the Department of Hematology, Affiliated Hospital of Xuzhou Medical University, were collected to preform the morphological analysis in bone marrow and peripheral blood smears. Based on the comprehensive diagnosis results of morphology, immunology, cytogenetics, and molecular biology, comparison between acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL), AML with RUNX1-RUNXITI gene, AML with CBFβ/MYH11 gene, acute promyelocytic leukemia (APL) with PML/RARA gene, AML with NPM1 gene, the rest of the AML, Ph+ALL and Ph-ALL were performed by Chi-square test along with analysis of the differences in the ratio of wood bundle cells, pseudo-Chediak-Higashi (PCH) inclusions, cytoplasmic small particles, nuclear notches, leukemia cells with cup-like changes (cup cells); as well as the differences in the micromeganuclei, early immature granulocytes, plasma cells, high eosinophils and other accompanying cells and the distribution of "grape-like" aggregation. Finally, the morphological characteristics of acute leukemia cells, the appearance and arrangement of accompanying cells were summarized.Results:Between AML and ALL, there were statistically significant differences in cytoplasmic Auer bodies[(45.5%, 0%), χ 2=211.400, P<0.01], PCH inclusion bodies[(28.9%, 0%), χ 2=114.100, P<0.01], cytoplasmic fine particles[(20.7%, 2.9%), χ 2=53.798, P<0.01], nuclear notches[(0.7%, 6.1%), χ 2=30.906, P<0.01], and goblet cells[(4.9%, 0.3%), χ 2=13.495, P<0.01], micromegakaryus [(22.4%, 0.3%), χ 2=80.398, P<0.01], plasma cells[(87.6%, 10.6%), χ 2=604.241, P<0.01], hyperacidophils[(15.3%, 1.0%), χ 2=46.116, P<0.01] showed significant differences in the "grape-like" aggregation distribution. In AML with RUNX1-RUNXITI gene, the changes of vacuoles and PCH inclusion bodies are more obvious; in AML with CBFβ/MYH11 gene, the increase of hypereosinophils is more obvious; in APL with PML/RARA gene, the increase of woodbundle is more obvious. The morphology of nuclei chromatin, nucleolus, and vacuoles were also different among the groups. Comparison between Ph+ALL and Ph-ALL showed that Ph+ALL was more prone to develop early immature granulocytes and plasma cells (all P<0.05). Conclusion:There are significant differences between AML and ALL in the characteristics of leukemia cells, the regularity of accompanying cells, and the aggregation and distribution patterns. The subtypes of AML with specific genetic abnormalities have their own characteristics in the appearance of vacuoles, PCH inclusions, hypereosinophils, woodbundle cells, and goblet cells. Ph+ALL is more prone to present early immature granulocytes and plasma cells.