Abstract： Objective To explore the effects of endoscopic third ventricuiostomy in treatment of chronic complicated hydrocephalus. Method The clinical data of 15 cases of chronic complicated hydroephalus with endoscopic third ventriculostomy were analyzed retrospectively. Results Satisfying post -operative results were obtained in 15 cases. No complications occurred. One patient suffered recurrent hydrocephalus after first operation and underwent second third ventriculostomy. During operation orificium fistuloe was closed and patient recurred well after operation. Conclusions Endoscopic third ventriculostomy is reliable and effective in treatment of chronic complicated hydrocephalus.