Objective To investigate the effect of (Pyr1)apelin-13 on the proliferation and activation of Jurkat T lymphocytes. Methods Jurkat T cells were treated by 0, 10, 50 nmol/L (Pyr1)apelin-13 for 24 hours and cell proliferation ability was detected by CCK-8 assay. The effect of (Pyr1)apelin-13 on the activation of Jurkat T lymphocytes with anti-CD3 and anti-CD28 antibodies was observed and the molecular mechanism was investigated. Quantitative real-time PCR was applied to detect the expressions of CD69, CD25, cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed death-1 (PD-1) mRNAs. Results The proliferation of Jurkat T cells was not affected by (Pyr1) apelin-13. However, (Pyr1)apelin-13 increased the expressions of CD69 and CD25 and then activated Jurkat T lymphocytes. Furthermore, the expressions of CTLA-4 and PD-1 had no difference between activation group and (Pyr1)apelin-13 group. Conclusion (Pyr1)apelin-13 promotes Jurkat T lymphocyte activation by increasing the expressions of CD69 and CD25.