In order to indicate the distribution, degree and duration of myasthenia gravis, Osseman’s modified typing method is now generally used to classify myasthenia gravis into the following types: ① Type I: ocular muscle type, the lesion is limited to the extraocular muscles only, and other muscle groups are not involved within two years. Type IIA: Mild generalized type, the limb muscles are often involved with the eye muscles, the limb muscles are mildly involved with or without the extraocular muscles, usually without mastication, swallowing and dysarthria, and can take care of themselves. Type IIB: Moderate generalized type, often with ocular muscle involvement in the limb muscle groups, moderate involvement in the limb muscle groups, with or without extraocular muscle involvement, usually with chewing, swallowing and dysarthria, and difficulty in self-care. Type III: severe radical type with rapid onset and progression, involving pharyngeal muscles within a few weeks or months of onset, respiratory muscles within six months, with or without extraocular muscle involvement, and difficulty in self-care. ⑤ Type IV: late-onset severe disease, insidious onset, slow progression, starting with type I, IIA, IIB, gradually developing to involve the respiratory muscles within two years. Type V: myasthenia gravis, with skeletal muscle atrophy appearing within six months of onset. The above subtypes are not definitively divided. Clinically, the type of presentation varies with remission, relapse or worsening of the disease, and is often mixed, except that a certain type is more prominent during the course of the disease. In children, MG is usually characterized by simple ocular muscle type, while in adults, although the disease is initially characterized by ocular muscle weakness, it mostly develops into a generalized type after a few months or years.