Abstract: Objective To investigate the mechanisms of Mn neurotoxicity basing on neurons model dealed with Mn in vitro.Methods Mature cortical neurons were incubated with Mn of different dosages(0.2,0.6,1.0 mol/L)for 24 hours.The morphological changes in neurons were observed with light microscope and DNA damage was determined through single cells gel electrophoresis(SCGE).The length of comettail and the percent of comet like neurons were applied to score DNA damage.Results Mn could cause obvious morphological change under light microscope and DNA damage by SCGE.The length of come t tail was(117.3±30.8),(136.6±29.0),(218.7±22.6)μm.The percent of comet like neurons was 40%,43%,96% in different Mn-treated groups respectively.These two indexes in Mn treated groups were hig her than that of in control(184.1~11.8)μm,15%(P<0.01).DNA damage was specially serious in higher Mn group than that of in lower and medium Mn groups(P<0.01).Conclusion Mn could induce morphological change and the damage of DNA in neurons.