Cerebellar underdevelopment can be characterized by poor balance, head tremors, fine motor deficits, and speech disorders. Cerebellar underdevelopment usually refers to the dysfunction of the cerebellum caused by congenital underdevelopment or acquired diseases. 1. Low balance ability: when the patient has cerebellar underdevelopment, he/she may show decreased balance ability, unsteady walking, unsteady holding, poor coordination of legs, and easy to fall down when walking. This situation should be diagnosed clearly after magnetic brain examination and treated symptomatically, and balance training can also be carried out with the rehabilitation department to improve the balance ability of the cerebellum. 2. Head trembling: Head trembling, such as nodding and shaking of the head, may occur when the cerebellum is underdeveloped, and nystagmus and ankylosis may also occur in severe cases. The treatment should be chosen according to the severity of the disease. 3. Fine motor disorders: Patients with cerebellar underdevelopment may have difficulties in fine motor skills such as writing and tying shoes. 4. Language disorders: cerebellar hypoplasia can also affect the language center, resulting in poor speech. When there is cerebellar underdevelopment, it is necessary to go to the hospital in time for detailed examination, and cooperate with the doctor to carry out standardized treatment, so as to avoid the progress of the disease affecting the life.