Due to the widespread trust threat under the open and dynamic Internet environment, the computer community has endeavored to engage in the studies of technologies for protecting and evaluating trustworthiness. This paper firstly defines trust from three aspects: trust relationship, trust property and trust entity, and build a uniform view for multiple trust properties. Secondly, according to the common characteristics over varied trust properties, a model of trust management is elaborated, in which the trust entities, measurement model and trust policy are described. Thirdly, the trust management is implemented as a kind of public service on a J2EEcompliant middleware platform, i.e., the PKUAS.