Abstract: 　Objective　To analyze the clinical data of an infant with Chiari II malformation so as to deepen understanding of this disease in pediatrics. Methods The clinical, laboratory and imaging data of an infant with Chiari II malformation were retrospectively analyzed and a literature review was performed. Results A 2-month-old male infant was admitted to our hospital due to a neck tumor for two months. Brain magnetic resonance imaging (MRI) showed herniation of the cerebellar tonsils into the foramen magnum. The infant was finally diagnosed with Chiari II malformation based on the result of MRI and the presence of myelomeningocele. After repair of spinal cord and meninges and decompression of pillow macroporous by surgery, the infant presented with intermittent fever and progressively enlarged anterior fontanel, with culture-positive cerebrospinal fluid for bacteria and hydrocephalus diagnosed by CT, and intracranial infection was considered. Ventriculoperitoneal shunt was not performed due to uncontrolled intracranial infection after treatment, and motor retardation was found during the follow-up. Conclusions Chiari II malformation may results in nervous system dysfunction with poor diagnosis and high case fatality rate. Early diagnosis and operation may be helpful to the improvement of prognosis.#br#Key words:　Chiari malformation II type;　brainstem symptoms;　prognosis#br#