To provide a UML design method by which architecture design pursuing optimal design parameters while viewing the overall target system on the UML model can be performed. A UML design method of the present invention is a UML design method for performing design by modeling a target system based on Unified Modeling Language (UML), using a profile storing a design parameter, the method including the steps of: storing a stereotype and a tagged value in the profile as the design parameters; annotating a UML model of the target system with the stored stereotype and tagged value; and associating the added stereotype and tagged value with each class constituting the UML model, and displaying the stereotype and tagged value and the UML model, which are associated, on a graphical user interface.