Abstract: Objective To explore the method and effect of simultaneous EEG-fMRI technique in localization of epileptic foci.Method Simultaneous EEG-fMRI examination was performed before operation in 13 patients with refractory epilepsy.fMRI data was analyzed to find out the blood oxygenation level dependent(BOLD)signal changes in brain according to the time course when spikes appeared in the EEG data. Then the consistency was analyzed between activitied area in fMRI and epileptic foci determined by neuro-electrophysiological methods.Results In 9 cases epileptic foci and the activated regions were consistent with each other very well In the other 4 cases the activated area in fMRl was larger than the regions of epileptic foci, but the most active area was consisted with the epileptic foci. Condusions Simultaneous EEG-fMRI,an non-invasive technology combining the localization of anatomy and function,could determine the location of epileptic foci precisely.