Abstract: Objective To investigate the change of nitric oxide synthase one(NOS1)activity in temple and frontal lobe of AD rat after 96dB wide frequency noise exposure.Methods Western Blot and image quantitative analysis technique,combined with auditory brainstem response(ABR)measurement.Results Before injection of glutamatic acid in two sides of hippocampus CA1,memoried rats are 69.6% after 24 hours by electric stimulation,but is only 14.7% after injury and differences are very notable(P<0.01).Contrast of ABR threshold from beginning to end in three group of rats is very mar ked(P<0.01).ABR threshold contrasted with two group control,that of rating lutamatic acid group before being given noise stimulation are remar kable(P<0.05).expression of NOS1 in temple and frontal lobe of glutamatic acid group are much more than those of themselves after being given noise stimulation.Conclusion Wide band frequency noise can reduce the expression of NOS1 in temple and frontal lobe of AD model rat.