The completeness and correctness of requirement modeling is the crucial factor that affecting the success of the system development. Use case diagram is the standard tool for modeling the use requirement for the objected-oriented systems analysis and design. However, to model the sequence diagram in the platform independent model (PIM) stage is still not a straightforward task to identify objects, operations and their relationships from the use case diagram. Robustness analysis has been proposed to bridge this gap between the user requirement modeling and the PIM modeling. However, the detailed guideline for the robustness analysis is lacking, while it is important for designer to enhance the completeness and correctness of the user requirement modeling. To alleviate the forgoing problem, we proposed that use case diagram, activity diagram and robustness diagram are used to represent the use requirement. Once a use case diagram is constructed, the activity diagram is used to describe the activity flow and the associated input/output of each use case. Finally, the robustness analysis with the guideline proposed is used to help the identification of boundary, control, and entity objects and enhance the completeness of the user requirement. The outcome can then be used to construct a sequence diagram in the PIM. A real-world case is presented to illustrate the feasibility of using the proposed method. With this methodology, the system developer can enhance the completeness and correctness of user requirement efficiently and thereby reduce the risk of success development failure.