Nowadays, social network site (SNS) has been a popular platform for information sharing and dissemination. However, because of unknown information sources or unfamiliar recommenders, users of SNS may receive thousands of recommending information, which contain potential risks to receivers. To meet the challenge of confirming reliabilities of recommendations, a novel method of recommended trust computation is proposed in this paper. Firstly, according to the elements of users' relationships and community characteristics in SNS, concepts of belief and reputation are defined to express subjective trustable relationship among individuals and objective trust view. Then, recommended trust computation is presented on the basis of aforementioned two concepts. The recommended trust computation is divided into two aspects, that is, recommended trust computation with different route composition and recommendation optional confidence. Further, a SNS recommended trust computation framework is proposed. Finally, examinations are given to further explain the efficiency and feasibility of our mechanism. Copyright © 2014 John Wiley & Sons, Ltd.