In recent years, IT companies offer various cloud services using hardware-based technologies or software-based technologies. User can access these cloud services without the constraints of location or devices. The technologies are virtualization, provisioning, and big data processing. However, security incidents are constantly occurring even with these techniques. Thus, many companies build and operate private cloud service to prevent the leak of critical data. If virtual environment are different according to user permission, many system are needed, and user should login several virtual system to execute an program. In this paper, I suggest the access control method for application software on virtual operating system using the Open Authentication protocol in the Cloud system.