Disclosed are a composition for treating motor neuron diseases and a use thereof. Each unit of the pharmaceutical composition contains 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 motor neuron diseases, and can be used to prepare drugs or health care products for the treatment of motor neuron diseases. The composition has the advantages of being safe, having no side effects during long-term use, low cost of treatment, a good effect, and being suitable for clinical promotion.
