A composition for treating motor neuron diseases (MNDs) and use thereof are provided. Each unit of the composition comprises 0.3 to 8 g of L-ornithine or an L-ornithine salt with an L-ornithine content equivalent to 0.3 to 8 g, 0.5 to 5 g of aspartic acid, and 2 to 20 g of vitamin B6. The composition can ameliorate or even reverse the progression of MNDs, and can be used to prepare drugs or healthcare products for the treatment of MNDs. The composition has the advantages of being safe and having no side effects during long-term use, low cost of treatment, good effect, thus being suitable for clinical promotion.
