Abstract： Objective To study modified hemispherectomy in treatment intractable epilepsy caused by lateral lesion of hemisphere.Methods 58 cases treated by hemispherectomywere retrospectively summariedin our ward fromNOV,2006 -July,2011.The epileptogenic hemispheres were determinted by analisising these patients' clinicalfeature,neuroimaging and scalp EEG.Their existent and prediction of post - surgicalneurofunction were evaluated by fMRI and/or PET - CT and/or DTI.In the end the surgical plan were made include the scalp insicion and whether remaining the eloquent areas.Results All of 58 patients received hemispherctomy,32 cases were left side,26 right side,5 cases remained the partial motor cortex according the fMRI.There was no severe complication and death occurred,only 4 patients had little hemorrhage in the postoperative cavity,5 patients had poor wound healing for local ischemia and leakage of CSF.Patients were followed up from one year to 5 years and 8 months,48 patients (83％) were seizure free,10 patients( 17％ ) had some seizures in various degree.In Engle criteria,48 patients(83％ ) were Engle class Ⅰ,7 patients(12％ ) were Engle class Ⅱ,3 patients(5％ ) were Engle class Ⅲ.Conclusion Hemispherectomy is most effective treatment forintractable epilepsy caused by lateral lesion of hemisphere,for its excent in seizure control and no severe complication and better behavior and intelligence.Obviously,ourmodified hemisphrectomyhad advantage in seizure control to the intractableepilepsy caused by lateral lesion of hemisphere.advantage advantage.