Social network and Cloud Computing environment have become popular as a medium for connecting like-minded people and disseminating information. The public accessibility of such environment with the ability to share opinions, thoughts, information, and experience offers great promise to enterprises and users. But the public of information also take the risk of your profile is Exposed to strangers. Data publishing has attracted much interest in research community due to the important concerns over the protection of individuals privacy. As a result several mechanisms with different notions of privacy have been proposed to measure, set and compare the level of privacy protection. In this paper, we propose a novel trust based framework for representing a formal model to evaluating privacy. we consider trust as the reason of privacy, user share their secret or information According to the level of trust, then we decide the privacy value from trust value,using the existing network’s topology calculate trust value for the new contacts. We show that we can deterministic reduce the information leak and protect user’s privacy.