Aim To explore whether mitogen-activated protein kinase-interacting kinase-2 (MNK2) facilitates cardiac repair by inhibiting cardiomyocyte apoptosis induced by hypoxia and reoxygenation in mice and its underlying molecular mechanisms. Methods The cardiomyocyte hypoxia/reoxygenation (H/R) model was induced in vitro. The experimental groups were H/R+virus vector group, H/R+MNK2 overexpression adenovirus group and H/R+siRNA-MNK2 knockdown adenovirus group. Adult mouse heart ischemia/reperfusion (I/R) injury model was induced in vivo. The experimental groups were I/R+virus vector group and I/R+MNK2 overexpression adenovirus group. Western blot was used to detect the expressions of MNK2, p-MNK2,Bü lymphoma 2 related protein (Bax) and B lymphoma 2 (Bcl-2); Terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL) was used to detect the level of cardiomyocyte apoptosis; Echocardiography was used to detect cardiac function. Subsequently, the primary cardiomyocytes of H/R+MNK2 overexpression adenovirus group and H/R+virus vector group were used to perform RNA sequencing (RNA-seq). Differential gene enrichment and Kyoto Encyclopedia of genes and genomes (KEGG) were used to analyze the mechanism of anti-apoptotic effect of MNK2. The related cAMP signal pathway was found. Finally, the regulatory relationship between MNK2 and cAMP/PKA-CREB signal pathway was explored through rescue experiments. Results The expression level of p-MNK2 was significantly increased in H/R model group and I/R model group than that in the control group. In vitro, overexpression of MNK2 significantly increased the levels of MNK2 and p-MNK2 expression in cardiomyocytes. At the same time, it was found that the expression of apoptosis index protein Bcl-2 increased, Bax decreased, and the number of apoptotic cardiomyocytes reduced by 69.16% (all P＜0.05); Transfection of siRNA-MNK2 decreased the expression of Bcl-2, increased the expression of Bax significantly; In vivo, compared with the I/R+virus vector group, the cardiac function of the I/R+MNK2 overexpression adenovirus group showed no significant difference at 1 hour after I/R, while recovered significantly at 3 days after operation, in which the ejection fraction increased by 36.24% and the short axis shortening rate increased by 46.19% (all P＜0.05); TUNEL staining showed that myocardial apoptosis in I/R+MNK2 overexpression group decreased significantly by 28.65% (P＜0.05). Subsequently, the involvement of cAMP signaling pathway was confirmed by RNA-seq, bioinformatics analysis and relevant experimental verification. Experiments showed that overexpression of MNK2 activated cAMP/PKA-CREB signal pathway and the inhibition of PKA would enhance cardiomyocyte apoptosis inhibited by the overexpression of MNK2. Conclusion Overexpression of MNK2 can significantly inhibit apoptosis of mouse cardiomyocytes after H/R and improve cardiac function by activating cAMP/PKA-CREB signaling pathway.