Targeted therapy is a potentially useful approach for the treatment of T-lineage acute lymphoblastic leukaemia. This study aimed to find a highly effective, low toxic anti-tumour drug and further investigate its mechanisms. Jurkat cells were used as the object and were stimulated by different concentrations of crocin. By cell count, growth curve, methyl thiazolyl tetrazolium (MTT) method for the detection of cell proliferation, annexin V/propidium iodide (PI) method for the apoptosis rates, and reverse transcription-polymerase chain reaction (RT-PCR) for Bcl-2 and Bax gene expression, the effect and mechanisms of proliferative inhibition of crocin on Jurkat cells were further explored. Crocin promoted Jurkat cell apoptosis and inhibited cell growth, in a dose-time-dependent manner. The mechanism might be related to the inhibition of Bcl-2 gene expression and the promotion of Bax gene expression. These results suggest that crocin can be used as a suitable clinical agent for the treatment of T-lineage acute lymphoblastic leukaemia.