〔Abstract〕 Objective To investigate the promoter methylation level of the cytokine signaling 3(SOCS3) inchildren with acute lymphoblastic leukemia(ALL), and to explore its correlation with the treatment outcome and prognosis for ALL children. Methods The SOCS3 mRNA and methylation levels in bone marrow mononuclear cells were detected in 83 cases of newly diagnosed ALL at initial diagnosis, completely remission, relapse and 21 healthy control children through reverse transcription quantitative polymerase chain reaction(qRT-PCR) and methylation-specific PCR, respectively. SPSS 17.0 software was employed for statistical analysis to analyze the relationship between the level of SOCS3 mRNA expression and the methylation level of SOCS3 gene, the relationship between the methylation level of SOCS3 and the treatment outcome of the children with ALL. Meanwhile, The methylation level of SOCS3 gene in children with ALL was classified into high or low level group by the median method. The correlations of SOCS3 methylation status with the cumulative incidence of relapse rate(CIR) and overall survival rate(OS) were compared. Results The SOCS3 mRNA expression levels in initial diagnosis group and relapse group were remarkably lower than that in healthy control group(P<0.05). The methylation level of SOCS3 in ALL children was evidently higher than that in healthy control group(P<0.05). The results of 42 months follow-up showed that the CIR in high level group was dramatically higher than that in low level group(P<0.05), but there was no significant difference in the OS between these two groups(P>0.05). Conclusion SOCS3 methylation leads to low expression of SOCS3, and monitoring the SOCS3 methylation level can help to understand the treatment outcome and prognosis for ALL children.