This paper researches the textual structure and metaphor mode of academic discourse with“genre analysis theory”and“grammatical metaphor theory”. The Chinese abstract of academic thesis is a typical sample of academic discourse, which was not be payed sufficient attention to in past research. It builds a corpus of Chinese linguistic thesis abstract, from which this paper concludes that the basic form of textual structure of academic discourse is BIMRD mode besides other four variation forms, and the metaphor mode consists of grammatical metaphor and cognitive metaphor with the relationship of complementation, in which nominalization plays a role in achieving stylistic feature in academic discourse. Meanwhile, this paper discusses the feasibility and applicability when foreign theories are used in Chinese context. The research result is expected to apply to academic discourse writing and teaching.