Abstract: Objective: To make a further study of the reality ship between CT and clinical data of external hydrocephalus (EH). Materials and Methods: For this study. 24 cases with CT data were collected, Grandiose cerebral CT scanning and clinical examination were performed in 10 cases. Results: The CT feature was as follows: enlarged subbrachial space, enlarged cistern of longitudinal fissure of cerebrum. most of these cases complied with enlarged cistern ambient. The results of followed examination was as follow: typical changes of EH appeared at 3 th months. recovery began form 6-12th months completely recovery before 24 months. while the clinical symptoms disappeared. Conclusion: EH is a self-limited entity in early baby. most cases restore to normal condition.