To utilize technology of various areas effectively and efficiently, a grid enabled problem solving environment for bioinformatics (PSE-Bio) is built. This paper describes the architecture of PSE-Bio and proposes the new layer, Agent bundle, based on classical architecture with three layers. As a service bundle, Agent provides common single mechanism to access grid services, by which portal services can communicate with key grid components. Agent bundle not only search and select appropriate software in grid, but also have strategies to reuse local legacy program to save time and cost. Users can utilize PSE-Bio easily without any details about grid technology because PSE-Bio is serviceoriented. An example application of PSE-Bio workflow is implemented. Keywords: Grid, Problem Solving Environment, Service-Oriented Architecture, workflow, Bioinformatics The project is supported by Shanghai Natural Science Foundation 05ZR14050 Corresponding Author. Corresponding Author.