Objective To research the children's neurocognitive function changes after third ventriculostomy of hydrocephalus.Methods We retrospectively analyzed the medical files of 43 cases of children with hydrocephalus,including the endoscopic third ventriculostomy of 20 cases (Operation Group).The data regarding CT/MRI,EEG,SPECT,developmental quotient (DQ) before and after surgery were studied.We eveluated the children neurocognitive function recovery time and degree effect in postoperative stage.Surgery was not done in 23 cases (without operation group),in which developmental quotient (DQ)is measured after two weeks,2 month and 6 months of the diagnosis.Results The two groups after 2 month and 6 months of operation were compared developmental quotient difference were significant (P ＜ 0.05).In operation group:2 month and 6 months after operation compared with the preoperative developmental quotient difference were significant (P ＜ 0.01),operation group developmental quotient (DQ) value showed ascendant trend change (P ＜ 0.01).Comparing with the preoperative.postoperative ventricle size did not change significantly.The EEG abnormal rate,ECT cerebral blood perfusion imaging comparing with preoperative difference were significant (P ＜ 0.01),with a statistical significance.Conclusions Children after ETV can make neurocognitive function recovery,postoperative ventricular size change and improve is not obvious.