Abstract： Objective To investigate the mean survival time and risk factors of amyotrophic lateral sclerosis(ALS).Methods Sixty-five ALS patients were followed up,and the clinical data of 33 of them who died were retrospectively analyzed.The survival time and related risk factors were analvsed with the statistic tools such as Kaplan-Meier survival curve,t test, and variance analysis.Results The mean survival time of the 33 patients was(35±19)months from onset of symptom.The mean survival time for the patients＜60 years old was(39±19)months;not signgicantly different from that of the patients aged ≥60years [(30±18)months,P＞0.05].The mean survival time from confirmed diagnosis was(22±17)montns.The risk factors influencing the survival time of ALS patyients were age,site of onset,severity of disease,and interval between symptom onset and diagnosis.Conclusion The prognosis of the ALS patients with elder age,bulbar onset,more severe symptoms and signs,and shorter confirmation time is poorer.