Cloud Computing is a set of IT Services that are provided to a customer over a network and these services are delivered by third party provider who owns the infrastructure and reduce the burden at user's end. Nowadays researchers devoted their work access control method to enhance the security on Cloud. RBAC is attractive access model because the number of roles is significantly less hence users can be easily classified according to their roles. The Role-based Access Control (RBAC) model provides efficient way to manage access to information while reducing the cost of security administration and complexity in large networked applications. This paper specify various policies in RBAC on clouds such as migration policy which helps the user to migrate the database schema and roles easily to the Cloud using XML with more security. Restriction policy provide the security enhancement in Role Based Access Model by restricting the number of transaction per user and if the number of transactions will increase the admin will come to know through its monitoring system that unauthorized access has been made and it would be easier to take action against such happening. This paper proposes backup and restoration policy in Role Based Access Model in which if the main cloud is crashed or not working properly then the backup and restoration facility will be available to avoid the lost of important data. In this case chances of loss of data are very less so enhance more security on Cloud Computing.