·AIM:To explore the etiology,clinical features of diplopia.·METHODS:Visual acuity,eye movement and diplopia of 45 patients with diplopia were examined,and blood biochemical examination and image diagnosis were performed to analyzed the cause of diplopia.·RESULTS:Among 45 patients with diplopia,monocular diplopia was in 3 cases(7%),42 cases with binocular diplopia accounted for 93%.Among binocular diplopia,29 cases was neurogenic 64%,of whith 12 cases was cerebral thrombosis,cerebral hemorrh-age in 7 cases,intracranial vascular tumor was in 1 case,4 cases of intracranial tumors,1 case of traumatic brain injury,nasopharyngeal carcinoma was in 1 case,3 cases of flu.3 cases of muscle-derived Graves disease accounted for 7%;neuromuscular junction lesions was in 1 case(2%),machinery was in 5 cases(11%),2 cases of unknown cause accounted for(4%).·CONCLUSION:The main casuses of diplopia were cerebrovascular disease,trauma and brain tumor.·