Objective To investigate the effect of CrkL silence on hypoxia/reoxygenation (H/R)-induced apoptosis and survival inhibition in cardiomyocytes and the underlying mechanisms. Methods H9C2 cardiomyocytes were infected with blank, negative lentivirus and CrkL RNAi lentivirus (CrkL mRNA silence), and then treated with H/R separately. The cardiomyocytes were divided into blank group, negative lentivirus group, CrkL silence group, blank + H/R group, negative lentivirus H/R group and CrkL silence H/R group. The expression of CrkL mRNA was detected by RT-PCR, and the expression of CrkL and p-ERK1/2 protein was detected by Western blotting analysis. The apoptosis rate of cardiomyocytes was analyzed by flow cytometry, and the cell proliferation rate was analyzed by MTT. Results Compared with blank and negative lentivirus groups, CrkL silence group had significantly decreased CrkL mRNA and protein, p-ERK1 protein, p-ERK1/2 protein and proliferation rate(P<0.05 or P<0.01), and significantly increased apoptosis rate(P<0.01). The same was true for CrkL silence H/R group when compared with the blank H/R and negative lentivirus H/R groups. Conclusion CrkL silence can aggravate H/R-induced apoptosis and survival inhibition in cardiomyocytes, which might be mediated by the decrease of p-ERK1/2 protein expression.