Objective To study the time course and degree of optic nerve injury in rats with acute methanol intoxication. Methods Sprague-Dawley rats were fed methanol orally and sacrificed at different point of time after the gavage. Blood samples were taken for methanol concentration measurement, and optic nerves were removed for pathological examination. Results In rats taken methanol to the dose of LD50, significant optic nerve injury began after 2 hours. The injury progressed along with time and reached the peak after 4 hours. In rats taken methanol to the dose of LD0, optic nerve injury reached the peak after 8 hours. In both groups of rats, optic nerve injury persisted even though blood methanol concentration became lower after 24h, 48h and 72h of methanol administration. Conclusion Optic nerve injury occurs as early as half an hour after acute methanol intoxication. The injury degree is related to the dose and blood concentration of methanol. Optic nerve injury reaches the peak after the presence of the highest blood methanol concentration for 4 hours. Optic nerve injury persists even though blood methanol concentration goes down after the methanol administration.