The purpose of this study is to establish a theoretical basis for multi-layered sentence-extension education by investigating the ‘structure-function-genre and ideology’ layers of sentence-extension. Sentence-extension education at present is problematic because it is limited to the structure layer and it is obscure on the function layer. Moreover on the genre and ideology layers no educational content exists. We therefore focus first on sentence-extension education for the function layer from the viewpoints of systematic functional linguistics and theory of information structure. Then we discuss the genre and ideology layers from the viewpoints of genre as a social practice and critical discourse analysis. Last, we suggest that further study on and description of these phenomena should be done in order to enrich the content of multi-layered sentence-extension education.