A framework model is put forward to design multimedia digital watermarking detection system based on watermark mobile agent, then a modular structure of watermark mobile agent and watermark mobile agent service environment is proposed on the basis of the framework model. In addition, an effective solution by using the blackboard mechanism and the dynamic itineraries strategy is proposed to solve multiagents communication and migratory route of watermark mobile agent. The experimental result validates that the proposed system can effectively detect the watermark embedded in multimedia data by using characteristic of the watermark mobile agent that routes from host to host on a network. The proposed system reduces network load by using migration of the watermark mobile agent to the remote host and it put effectively the technology of copyright protection of multimedia in practice.