To investigate the clinical manifestations, treatment and prevention of optic nerve damage by ethambutol toxicity.Retrospective analysis was done on 17 patients of tuberculosis who had been treated with ethambutol and shown ocular symptoms.Changes in visual acuity, fundal appearance, visual field and color sensation were major abnormal findings. According to the neural damage, the patients were diagnosed as axial neuritis 7 cases, periaxial neuritis 2 cases, mixed type 3 cases and there were no significant changes on fundus, color sensation or visual field in 5 cases. In 17 cases, none of the patient showed the appearance of retinitis. The impairment of visual acuity and the duration of damage were related to the daily dosage significantly. After stop of ethambutol and vasodilators or neurotrophic drugs were given, the function of optic nerves were recovered.To prevent the damage of optic nerves by the toxicity of ethambutol, the appropriate small dosage of ethambutol is recommended, regular examination and monitoring of visual function is necessary. The physicians should be fully aware of the diagnosis and clinical manifestations of ocular toxicity of ethambutol, as soon as the diagnosis is made, ethambutol should be stopped immediately and appropriate therapy should be given.