Abstract: A cloud enterprise application system is directly constructed in the cloud without installing to the individual use's computer devices. As the edition of the application is modified, and it is only needed to change the edition in the cloud structure. One enterprise has a dedicated database (sub-directory). All data generated by various application units are automatically stored in the dedicated sub-directory instead of the operation environments of the users. For one enterprise, all the application units performed by the enterprise are directed to the sub-directory of the enterprise. They directly access the data of the sub-directory specific to the enterprise. Thus the compatibility of the data between different application is high. The data files are not distributed in many different computers so that problems induced from data management are greatly reduced. Furthermore, the object of this system is to enterprises instead of individual users.