Objective To investigate the application of electrocorticography （ECoG） combined with deep electrode monitoring in surgery for symptomatic epilepsy and the influencing factors for treatment outcome.Methods A retrospective analysis was performed for the clinical data of 53 patients who were admitted to our hospital from January 2017 to December 2019 and underwent the surgery for symptomatic epilepsy. During the surgery， ECoG and deep electrodes were used to monitor and locate epileptogenic foci and determine the depth and extent of epileptic foci and surrounding epileptogenic foci for surgical resection. The patients were followed up for 12 months after surgery， and Engel classification was used to evaluate treatment outcome. The patients were divided into response group with 36 patients and non-response group with 17 patients according to the treatment outcome. Univariate and multivariate logistic regression analyses were used to investigate the influencing factors for the surgical outcome of symptomatic epilepsy.Results All patients completed the surgery successfully. During the surgery， both ECoG and deep electrodes detected paroxysmal or persistent spike and slow wave complex， spike waves， and sharp waves at focal cortical dysplasia （FCD） lesion， and in addition， deep electrodes detected spike and slow wave complex and sharp waves in normal brain tissue around FCD lesion， which had lower discharge degree and frequency than the waves detected in FCD lesion. After surgery， there were 2 patients with temporary mild hemiplegia of unilateral limb， 2 patients with language disorder， and 2 patients with apathy， which returned to normal at 2 months after surgery， and no serious infection or intracranial hemorrhage occurred after surgery. The multivariate logistic regression analysis showed that course of disease >2 years （odds ratio ［OR］ = 6.500， 95% confidence interval ［CI］： 1.741-24.274） and partial resection of epileptogenic foci （OR = 14.583， 95% CI： 1.545-137.661） were risk factors for the surgical outcome of symptomatic epilepsy， and no early onset after surgery （OR = 0.066， 95% CI： 0.012-0.368） was a protective factor for the surgical outcome of symptomatic epilepsy.Conclusions ECoG combined with deep electrode monitoring can accurately locate epileptogenic foci and determine their depth and extent during the surgery for symptomatic epilepsy. The course of the disease， extent of the resection of epileptogenic foci， and early seizures after surgery are influencing factors for the surgical outcome of symptomatic epilepsy.