Abstract: A virtual enterprise is a temporary and dynamic consortium composed of many different and geographically dispersed enterprises and organizations Its operation mechanism is much different from general ones Trust models of CA in existence, such as hierarchical models, peer to peer models and bridge CA models, and so on, do not agree with practical interactions of a virtual enterprise VCA （virtual CA） is a new way to solve this problem As the original scheme does not accord with the fact of a practical virtual enterprise, two typical cases are analyzed, and the characteristics and requirements of a virtual enterprise are pointed out in this paper And based on this analysis a new model of VCA is constructed and a new VCA scheme for virtual enterprises is proposed This new model and scheme suit the dynamic variety of a virtual enterprise, and avoid and prevent the dishonesty of some member