Abstract: ObjectiveThe effects of normobaric hypoxia on cognitive processing in human were studied by recording audio event-related potential(ERP)to diagnose possible damage of the brain.MethodsTen climbers(experimental group)and ten male subjects(control group)were recruited.Four differ ent oxygen concentrations:20.9%,16%,13% and 10% were chosen to demonstrate the hypoxic effects on human.The study applied the method to explain the cognitive function of climbers under various simulated high alt itude.ResultsIn experimental group,there was an increase in N100 amplitude component of ERP and a decrease in N100 latency component which were attributed to an accompanying decrease in oxygen saturation.The control group had no evident trend in the two components.In control group,in P300 amplitude between 10% oxygen concentration and sea level there was a significant difference(P<0.05),and there was an increase in P300 latency component which was attributed to an accompanying decrease in oxygen saturation,experimental group had no evident trend in the two components.There was a difference between experimental group and control group in P300 components(P<0.05).ConclusionLong-term hypoxic exposure may affect the function of attention and delay the evaluation step of information processing.