Abstract: Objective 　To investigate the expression and clonality of T cell receptor ( TCR) Vβ repertoire in cord blood T cells induced by PML-RARα peptide in vitro. Methods 　Cord blood mononuclear cells were amplified by IL-2, anti-CD3 and anti-CD28 antibody with different concent ration (16. 7μg / mL, 33. 3μg / mL or 50μg / mL respectively) of synthetic PML-RARαpeptide. The induced T cells were collected at different time point s af ter culture (3, 6, 9 or 12 days) . The expression and clonality of TCR Vβ subfamilies within induced T cells were analyzed by using RT-PCR and genescan technique. Results 　Restricted expression and cloanl expansion of TCR Vβ subfamily cord blood T cells could be identified after induction by PML-RARαpeptide. Conclusion 　The PML-RARα peptide could induce the clonal expansion T cells from cord blood in vitro, which may have specific cytotoxicity for PML-RARα+ cells.