Graphic user interface has become the mainstream of today¡¦s web-based systems. The object oriented technique and the diagrams from the Unified Modeling Language (UML) are becoming the major tools for modeling the platform independent model (PIM) of a web-based system. Once the PIM is constructed, the results can then be transformed into its platform specific model and template code based on the model driven architecture (MDA) approach. However, the detailed guideline for the transformation from PIM to the Microsoft .Net platform is lacking. Therefore, this study presents a methodology which provides guidelines for the transformation from PIM to Microsoft .Net platform for a web-based system. The research methodology is articulated using the design science research methodology. A usability evaluation with a real-world web-based system case is performed to demonstrate its applicability. The results indicated that with this proposed method, the system developer can effectively transform the PIM of a web-based system into its Microsoft .Net platform and template code.