This paper aims at identifying trust factors to be managed in UCC environment, and how those trust factors impact on trust in UCC site. Also this paper examines the moderating effect of level of UCC participation(UCC retrieve, UCC production) on the relation between trust in UCC site and intention to use. For this purpose, we identified information, system, service, and site trust through intensive review of prior researches and some expert interviews. A total 338 surveys were used to analyze research hypothesis. The findings show that information, system, and service trust is positively and significantly related to site trust, and then site trust has impact on UCC usage. But, It is proven that there is no difference in effect of site trust on UCC usage according to level of UCC participation.