Phrase Treebank is an important resource for Natural Language Processing research and practical application.For Vietnamese,we lack this kind of Treebank resources.This paper presents a method to construct the Vietnamese phrase Treebank by fusion of Vietnamese grammatical features and improved PCFG.This method can automatically analyze Vietnamese phrase structure tree and solve the problem of constructing the Vietnamese phrase Treebank.Firstly,Vietnamese grammatical feature set is established by analysis of Vietnamese grammatical features.Then,grammar rule set of PCFG model is obtained from manual annotation Vietnamese phrase trees.Finally,Vietnamese grammatical feature set is fused into improved PCFG model,which is regarded as a supplement,and the method completes the construction of Vietnamese phrase Treebank.The experimental results show that the accuracy of proposed PCFG model for the Vietnamese phrase Treebank construction reaches 89.12%.Compared to conventional PCFG model and the maximum entropy method,the accuracy obviously is improved.