目的：探讨无临床症状的缺铁性贫血（ＩＤＡ）小学生（分为补铁组和安慰组）治疗前后认知功能的改变。方法：采用智商（ＩＱ）、事件相关电位（ＥＲＰ）测试的方法对７０例ＩＤＡ、３０例正常小学生的认知功能进行对照测查。结果：与正常对照组比，两组ＩＤＡ儿童治疗前Ｐ３００潜伏期均明显延长，治疗３个月后补铁组Ｈｂ升高１０ｇ／Ｌ以上，复查ＥＰＲ，补铁组Ｐ３００潜伏期恢复，与治疗前比较差异有极显著意义（Ｐ＜００２），而与正常组比无统计学差异（Ｐ＞００５）。结论：Ｐ３００是客观评定儿童认知功能的敏感指标，可及早检出ＩＤＡ所致神经系统亚临床损害和可动态观察铁剂对认知障碍的疗效 Objective: To investigate the changes of cognitive function in IDA primary school students without clinical symptoms (divided into iron supplementation group and comfort group) before and after treatment. Methods: The cognitive function of 70 cases of IDA and 30 normal pupils were tested with IQ and ERP. Results: Compared with the normal control group, the latent period of P300 in two groups of IDA children was significantly prolonged. The Hb level in the iron-supplemented group was increased by 10g / L or more after 3 months of treatment. The EPR was rechecked and the latency of P300 was restored in the iron-supplemented group. Compared with the pre-treatment The difference was significant (P <002), but no significant difference with the normal group (P> 005). Conclusion: P300 is a sensitive index to objectively evaluate children’s cognitive function, which can early detect subclinical damage caused by IDA and observe the effect of iron on cognitive impairment