Abstract: Because existing theories and methodologies of design rational modeling can't fully describe the design rational in collaborative design.The existing design rational systems have great difficulties to be used in collaborative design.Taking the cognitive characteristics of collaborative design into consideration, this paper presents a design rationale model for team collaboration by improving the IBIS (issue-based information system) model.This design rationale model for team collaboration mainly includes seven kinds of essential factors:design problem, design scheme, design knowledge, design product, collaborative process, design scenario and design behavior.The first six kinds of factors are represented by different types of nodes, while design behavior, which describes the operation of the designer, is represented by the edges between different types of nodes.Finally, we take the design rational of the collaborative design of marking machine as an example to prove the feasibility and validity of this methodology.