Abstract: To examine the expression of SODD and Bcl - 2 proteins in bone marrow cells of acute leukemia (AL) in children and to detect a relationship, if any, with the classification, clinical features, therapeutic effects and prognosis of AL. Methods: Using the SABC method of immunohistochemical staining, the expression of SODD and Bcl- 2 proteins in the bone marrow cells of 86 cases with AL was detected. Results: The positive expression rates of SODD and Bcl- 2 in the first visit, relapse due to drug resistance and relief groups were obviously higher than that in the control group, with significant difference (P<0.05). There was no significant difference in the expression of SODD and Bcl- 2 proteins between the acute lymphoblastic leukemia (ALL) and acute nonlymphoblastic leukemia (ANLL) groups (t=1.874, t=1.583, P>0.05). The positive expression rates of SODD and Bcl- 2 in the pediatric patients with complete remission by chemotherapy were lower than that in the first visit pediatric patients, and there was a significant difference in the expressions (t=2.054, t=2.703, P<0.05). The expression of SODD protein in the refractory relapse group was higher than that in the initial treatment group (t=- 1.081, P<0.05). High expression of bcl- 2 protein occurred in both the first visit and refractor relapse groups, and there was no significant difference in the expressions (t=- 1.196, P>0.05), where-as the percentage of bcl- 2 positive cells in the refractory relapse group (45%～87%) was significantly higher compared to the first visit group (5%～62%) . The positive expression of SODD and bcl- 2 proteins in the high risk (HR) group were all significantly higher than that in the standard risk (SR) group (t=- 3.236, t=- 3.555, P<0.01), and Pearson rank correlation analysis indicated that there was a positive correlation between the expression of SODD and bcl- 2 proteins (P<0.01, r=0.726). In 30 pediatric patient with AL in the initial treatment group, negative expression of SODD was found in 13 patients and they had a complete remission (CR) rate of 84.6% (11/13), while in the other 17 cases with positive expression of SODD the CR rate was 64.7% (11/17). In 8 patients with negative expression of bcl- 2, the CR rate amounted to 100% (8/8), and in 22 cases with positive expression of bcl - 2, the CR rate reached 63.6% (14/22). Statistical analysis showed that the CR rates in patients with negative expression of SODD and bcl- 2 were all higher than those in the patients with positive SODD and bcl- 2 expression,with a significant difference (P<0.05). Conclusion: Expression of both SODD and Bcl- 2 plays a role in onset, progression, curative effect and prognosis of AL, and the two proteins may act synergistically in the onset and development of AL.