Objective：To investigate the neuroprotective mechanism of serum miRNA-181a on dopaminergic neurons in primary cell model of Parkinson’s disease induced by 1-methyl-4-phenyl-pyridinium (MPP+). Methods：Embryonic mouse mesencephalic primary neurons were cultured in vitro and divided into four groups：a blank control group, a MPP+ group, a miRNA-NC+MPP+ group, a miRNA-181a+MPP+ group. Dopaminergic neurons dendrites and axons were identified and counted by using tyrosine hydroxlase(TH) immunostaining under microscope in each group. Results：The dopamin(DA) neurons exhibited intact circular or triangular bodies and a variety of dendrites and axons derived from bodies, and had intact morphous and interweaved closely in the control group. The group treated by MPP+ were specifically found that the number of dopaminergic neurons decreased strikingly, axons and dendrites disappeared completely, and bodies remained. The axons appeared abnormal varicosities, apparent string-of-beads change. The axons and dendrites almost fragmented, only few cell bodies disappeared and exhibited axonal root. In the MPP+ group, the number of dopaminergic neurons increased, and cell bodies, axons, dendrites and the death of the dopaminergic neurons became improvement. Conclusion: The results suggested that miRNA-181a may play an important role in protecting dopaminergic neurons in MPP+ induced Parkinson’s disease.