Because the concept of stereotype in UML is not precisely defined

users and researchers often misused this kind of extension mechanism of UML

and modeling tools that support stereotype mechanism can not be well developed by the doctrine in UML.In this paper

we formally define the concept of stereotype in UML

and on this base

research the transformation from stereotype to meta model and the instructive rules of using stereotype.The research in this paper can help the user of stereotype understanding this kind of extension mechanism deeply

and provide reliable theory base for the development of modeling tools that support stereotype mechanism.