Overexposure manganese can induce neurotoxicity and apoptosis, in addition, miRNAs are widely involved in the apoptotic process of neurons. Therefore, it is crucial to explore the mechanism of miRNAs in manganese-induced neuronal apoptosis and then to find potential targets. Our present study showed that miR-143 expression was increased in striatum after exposure high doses of manganese. Then, we upregulated miR-143 expression via stereotaxic, and overexpression of miR-143 promoted apoptosis in striatal neurons. Further studies showed a negative regulatory relationship between miR-143 and ERK5, miR-143 upregulation decreased ERK5 mRNA level, inhibiting ERK5 signaling pathway, increasing the expression of Bax and Caspase-3, and exacerbating the apoptosis of striatal neurons. In conclusion, these results suggest that overexpression of miR-143 inhibited the ERK5 signaling pathway and promoted manganese-induced apoptosis in striatal neurons.