Abstract: Objective To investigate the mechanism of aluminum-induced impairments to cognitive ability,by studying the effect of chronic aluminum exposure on the protein expression of neurog ranin(Ng).Methods The ablactated Wistar rats were used to establish the chronic-aluminum-exposed models by the gavages of AlCl₃ of different concentrations in the drinking water.3 months later,the cognitive ability was tested by the experiment of diving tower method and the protein expression of Ng in hippocampi of rats was deter mined with Western Blotting.Results The concentration of aluminum in blood and brains of aluminum-exposed groups was obviously higher than that in control groups 03<0.01);The latent period in AlCl₃-exposed groups was shorter compared with that in control groups(P<0.01);the protein expr ession of Ng in the aluminum-exposed groups was lower than that in the AlCl₃-exposed groups.Conclusion Chronic aluminum exposure can not only increase the concentration of aluminum in blood and brains,but also reduce the protein expression of Ng,impairing the cognitive ability.