The availability of powerful processors and cheap storage devices as commodity components has improved large-scale distributed computing in PaaS cloud platforms. In a multi-user PaaS platform, resources, including computing units and data storage, should be shared between numbers of users. There is a great challenge in allocating and aggregating these resources for different users. In this paper, we present a design of scalable resource aggregation service in a multi-user PaaS platform. The design contains three parts: 1) a set of distributed, autonomous virtual computing nodes provided for every user, which are isolated from each other, 2) a task man-ager acting as user proxy in the system, responsible for controlling tasks and monitor runtime information, 3) a consistent resource view, which can be operated by the above distributed nodes with the same owner. We are implementing such a service in our prototype of networked concurrent computing environment named UniAS. In order to operate the system easily, we also implement a client shell for remote user. The future work is discussed at the end.