Abstract： Objective To examine the relationship between Hcy levels and clinical ALs.Methods In a cross-sectional study,21 amyotrophic lateral sclerosis patients were enrolled as ALS group and 40 healthy person as control group.The plasma Ievek of Hcy,B1,and fohte levels were measured in all subjects.Hcy levels were measured using highpefformance liquid chromatography with fluorescence detection.Results Patients with ALS had higher median plasma Hcy levels 17.65(17.65 ±11.23]us 10.32[10.32 4-6.72]μmol/L;P＜0.01)and lowerfolate levels9.52(9.52±2.57]us 13.56[13.56 4-3.23]ng/mL;P＜0.01),compared with controls.no significant difference was observed in plasma B12 levels between the two groups,651±112.34 pg/mL in ALS group,632±164.89 pg/mL in control group.Conclusion High plasma homocysteine(Hcy)levels was related with amyotrophic lateral sclerosis(ALS)compared with healthy controls and may be linked to pathophysiologic progression of the disease.