The invention discloses a software fuzzy self-adaptation modeling tool construction method based on expanded UML (Unified Modeling Language). The method comprises the following steps: as the method meets the UML2.0 specification, firstly, defining a software fuzzy self-adaptation meta facility by expanding the unified modeling language, wherein the meta facility comprises a stereotype as well as a mark value and a constraint condition corresponding to the stereotype, and generating a domain language; then, defining a domain model by utilizing the newly added meta facility, wherein the domain model comprises a plurality of views, including an analysis view, namely, a software fuzzy self-adaptation use case diagram, a structural view, namely, a software fuzzy self-adaptation class diagram, and a behavior view, namely, a software fuzzy self-adaptation sequence diagram; finally, defining the storage structures of the meta facility and the domain model by using XML (Extensive Markup Language), constructing software fuzzy self-adaptation domain plug-in, and establishing a complete modeling environment in combination with a unified modeling language tool. The method is compatible with a standard UML modeling environment, is convenient to construct, and is significant for improving the development efficiency of software fuzzy self-adaptation.