Nowadays many enterprises have to face a real problem in their operation processes, which is mismatch between active demands and resource. To solve this problem, traditional literatures employed Resource aggregation of Cloud Computing. However the most of these researches focus on computing resources but only few on application resources. And there does not exist a complete solution. In this paper, a resource service model RSM which is dynamic, customizable and fixable is presented. This model can be able to help enterprise add surplus resources into cloud resource pool. Then, a SaaS resource management architecture CARMA is built. The CARMA is used to solve the problems in sharing and management resource of enterprises. Meanwhile, resource optimization selection is taken into CARMA to reduce resource waste and task delay. Applied in the transport service field, practical work proved that the proposed models are feasible and achieve the expected effect.