This study reports the diagnosis and treatment of 2 children with isolated testicular recurrence (ITR) of acute B lymphoblastic leukemia (B-ALL) treated with CD 19 targeted chimeric antigen receptor T (CD 19 CAR-T) cells in May and December 2019 in the Department of Hematology and Oncology, Children′s Hospital of Soochow University, and explores the efficacy of CD 19 CAR-T cells therapy versus conventional radiotherapy and chemotherapy through literature review.Both cases were diagnosed as B-ALL by the morphologic, immunologic, cytogenetic and molecular biology methods.ITR was diagnosed by testicular biopsy at 60 months and 38 months after initial diagnosis in 2 cases, respectively.After infusion of CD 19 CAR-T cells at 7.0×10 6/kg and 1.5×10 7/kg, respectively for 7-10 days, testicular leukemia cell infiltration disappeared and complete remission was obtained.Among them, case 2 developed cytokine release syndrome and immune effector cell-related neurotoxicity syndrome after treatment, which was improved after drug intervention.It is suggested that CD 19 CAR-T cells are effective in the treatment of ITR in children, which may be an alternative to orchiectomy or local radiotherapy for ITR in children with B-ALL.