The object oriented software development is a kind of promising software methodology and leading to awholly new way for solving problems. In the research on the rapid construction of Structured Development Envi-ronment (SDE)that supports detailed design and coding in software development, a generator that can gener-ate the SDE has been applied as a metatool. The kernel of SDE is a syntax-directed editor based on the ob-ject-oriented concepts. The key issue in the design of SDE is how to represent the elements of target languagewith the class concept and a program internally. In this paper, the key concepts and design of the SDE and itsgenerator as well as the implementation of a prototype are to be discussed. The object oriented software development is a kind of promising software methodology and leading to awholly new way for solving problems. In the research on the rapid construction of Structured Development Envi-ronment (SDE) that supports detailed design and coding in software development, a generator that can gener-ate the SDE has been applied as a metatool. The kernel of SDE is a syntax-directed editor based on the ob-ject-oriented concepts. The key issue in the design of SDE is how to represent the elements of target languagewith the class concept and a program internally. In this paper, the key concepts and design of the SDE and itsgenerator as well as the implementation of a prototype are to be discussed.