The peer-to-peer (P2P) model which shares the content or resources over the network gradually replaces the traditional client/server architecture. A new computing architecture: Computing Power Services (CPS) which utilizes Web Services and Business Process Execution Language (BPEL) to overcome the problems of P2P about flexibility, compatibility and workflow management is proposed in this study. CPS is a lightweight Web Services based P2P power sharing environment, and suitable for enterprise computing works which are able to run in batch format in a trusty network. The architecture relies on BPEL which provides a visualized development environment and workflow control management. In this paper, the collaborated computing system has been applied to analyze the robustness of digital watermark by filter bank selection. As the result of this case, the performance can be improved in the aspect of speedup, efficiency and process time.