We　present　an　approach　for　privacy　preservation　in　cloud　computing　environment　in　which　we　propose　to　use　information　entropy　and　rough　set　theory　with　the　goal　of　personalized　privacy　protection　in　cloud　users　during　service　selection　based　on　trust.　In　the　approach,　cloud　server　is　as　an　active　service　provider　to　personalize　the　cloud　user　privacy,　cloud　user　selects　the　service　which　is　quantified　by　trust　for　multi-tenant　personalized　privacy　protection　needs.　We　descript　user　privacy　information　by　the　service　and　trust　attributes,　design　a　multi-attribute　service　quantization　algorithm　using　information　entropy　and　rough　set　theory　for　the　quality　of　service.　The　approach　can　achieve　the　purpose　of　quantitative　service　and　dynamically　adjust　the　supply　relationship　service　based　on　multi-attribute,　analysis　shows　which　can　effectively　protect　user　privacy　and　personalization　by　quantifying　the　cloud　service.　©　2015　SERSC.