Objective To explore the clinical characteristics of children with acute T-lymphoblastic leukemia (T-ALL) and analyze their relationship with prognosis. Methods A retrospective analysis was conducted on the clinical data and follow-up results of 50 children with T-ALL who were treated using the CCCG-ALL-2015 protocol at the Department of Hematology and Oncology, Children′s Hospital of Nanjing Medical University from November 2015 to December 2019. Kaplan-Meier survival analysis and Cox regression analysis were employed to identify factors affecting prognosis. Results Among the 50 T-ALL patients, there were 7 cases of relapse. There was no statistically significant difference in the baseline clinical data between the relapse group and the non-relapse group (P>0.05). However, the positive rate of minimal residual disease (MRD) (≥0.01%) on day 46 after induction remission therapy in the relapse group was significantly higher than that in the non-relapse group (P=0.037). The 5-year overall survival rate for the 50 patients was (87±5)%, and the 5-year event-free survival rate was (86±5)%. Multivariate Cox regression analysis indicated that the MRD level on day 46 after induction remission therapy was an independent prognostic factor (HR=0.104, 95%CI: 0.015-0.740, P=0.024). Conclusions MRD is of significant importance for the prognosis of T-ALL children. Personalized treatment should be provided based on MRD levels to prevent relapse and improve prognosis in these patients.