With increasing rate of storing and sharing information in the cloud by the users, data storage brings new challenges to the Extensible Markup Language (XML) database in big data environments. The efficient retrieval of data with protection and privacy issues for accessing mass data in the cloud is more and more important. Most of existing research about XML data query and retrieval focuses on efficiency or establishing the index, and so on. However, these methods or algorithms do not take into account the data and data structure for their own safety issues. Furthermore, traditional access control rules read XML document node in a dynamic environment, relevant dynamic querybased keyword research data security and privacy protection requirements are not many. In order to improve the search efficiency with security condition, this paper examines how to generate the sub-tree of matching keywords that the user can access by the access control rules for the user's role. The corresponding algorithm is proposed to achieve safe and efficient keywords search.