Hydrocephalus is a condition in which there is an increase in the amount of cerebrospinal fluid in the skull and an enlargement of the ventricular system or the subarachnoid space due to cranial disorders that cause excessive secretion or (and) impaired circulation and absorption of cerebrospinal fluid. In clinical practice, we need to make the right recommendations and diagnosis for any disease, so that we can treat the right symptoms and causes of the disease. The same is true for patients with hydrocephalus. However, what are the diagnostic criteria for hydrocephalus? The following is a detailed explanation. 1, congenital giant craniosynostosis: no hydrocephalus sign, negative sunset sign, no expansion of the ventricular system, no increased intracranial pressure, CT scan can confirm the diagnosis. 2.Recurrent intracranial tumor: Recurrent intracranial tumor often has enlarged head circumference or secondary hydrocephalus, ventriculography or CT scan and MRI can confirm the diagnosis. 3, slow subdural fluid or hematoma: often with a history of birth injury, the lesion can be unilateral or bilateral, often with optic disc edema, negative sunset sign. The diagnosis can be clearly confirmed by aspiration of hemorrhagic or yellowish fluid from the subdural cavity by fontanelle puncture. Cerebral angiography, CT or MRI can also be identified. 4, vitamin D shortage disease: head circumference can be increased in a square cranium, fontanelle expansion, tension is not high, and has the other manifestations of vitamin D shortage disease. 5, lateral ventricular injection of neutral phenol red 1m1, 2 to 12 minutes to do lumbar puncture, CSF visible phenol red, suggesting non-occlusive hydrocephalus. If 20 minutes CSF still does not see phenol red, suggesting blocked hydrocephalus. 6, CT or MRI scan can be seen in the ventricular system significantly expanded, sometimes can be detected hydrocephalus factors. 7.Cranial tuning line view or CT view shows enlarged cranial cavity, thinning of skull, separation of cranial suture and enlarged fontanelle. 8, cranial two-dimensional ultrasound view can be seen in the brain midline wave without displacement, while the ventricular system is expanded. 9, ventriculography, with filtered oxygen slowly injected in the ventricles, and then do X-ray view, can be observed ventricular expansion and cerebral cortex thinning. If the thickness of the cerebral cortex is more than 2 cm and the hydrocephalus can be lifted, it indicates that the patient is expected to recover intellectually. Ventriculography can also help to identify the site of blockage or to detect intracranial tumors. Ventriculography with gas or water-soluble iodine can reveal the shape and size of the ventricular system and the thickness of the cerebral cortex.