OBJECTIVE: To study the early and long term effect on velopharyngeal closure function by children adenoidectomy. METHOD: An investigation on parents or person who attended the children to be executed adenoidectomy, blowing soak test and computerized phonography were carried on 1 week, 1 month, and 3 monthes preoperatively and postoperatively, respectively. RESULT: 1) The investigation showed that 22 in 31cases presented hypernasality, in which 9 lasted more than 3 months after operation, Seven children presented nasal regurgitation of food and hypernasality only within 1 month. 2) Blowing soak test showed velopharyngeal insufficiency within 1 week (P <0.01) after operation. 3) Some voice figures appeared consonant and formants incomplete, and nasalization in the early period after operation. The value of F3 in /i:/ decreased after operation, especially within 1 week. CONCLUSION: Velopharyngeal insufficiency appears on most children after adenoidectomy transiently. There is no evidence shows a long term influence on velopharyngeal function for children after adenoidectomy.