Abstract: Objective T o detect the effects of 1 800 MHz electromagnetic irr adiation on hippocampus of rats.Methods Rats were randomly divided into three groups including 2 exper imental groups and 1 control.The experimental subjects were irradiated in the 1 800 MHz(continuous wave,CW)electromagnetic fields for 21 days(12h/d),their pow er density were 015 m W/cm² and 11 0 mW/cm².Mean while,sham-control was carried out.The effects on hippocampus of rats were observ ed and detected.Results No significant difference in PS range,change of PS slope and bringing of LTP were observed between exposure group and control group(P<0.05).Conclusion No findings of hippocampal slices induced LTP exists statistically significance between experimental groups and controls.