Objective To investigate the value of magnetoencephalograph(MEG)combined neuronavigation in the operation of frontal and temporal epilepsy caused by focal cortical dysplasia(FCD). Methods The data of 44 cases of frontal and temporal epilepsy caused by FCD were analyzed retrospectively. The location of epileptogenic zone and assessment IQ ,memory and language of patients were tested before operation;MEG examination confirmed the language dominance hemisphere and clarified the scope of language function. The surgical navigation system was guided by the American medtronic steal health 7 surgical navigation system to protect the neurological function. IQ,memory and language examination were measured 1 year after operation,and the data were analyzed before and after operation. The patients were followed up for 13~ 44 months after operation,according to Engel′s classification standard,the curative effect of epilepsy was determined. Results MEG can accurately localize the location of the language functional areas and FCD Epileptogenic zone. Of the 44 language functional areas ,28 had the left hemisphere and 16 were on the right side. Statistics showed that the verbal IQ and total IQ increased(P<0.05)in 1 year after operation,and there was no significant change in memory quotient and operation IQ(P >0.05). FCD patients recovered well ,and no language and limb function damaged. The curative effect of epilepsy:18 cases of Engel′sⅠgrade,22 cases of Engel′sⅡgrade;4 cases of Engel′sⅢgrade. Conclusions MEG combined with neuronavigation plays an important role in the localization ,localization and guidance of epileptogenic zone in patients with refractory frontal and temporal epilepsy caused by FCD ,which can protect the cortex function,avoid serious postoperative complications,and improve the therapeutic effect of epilepsy.