本文对两则国家级外语微课大赛获奖视频进行了多模态话语分析，在视觉语法和图文关系系统论的理论基础上构建出教育类多模态语篇的图文关系理论框架，对微课视频里视觉模态中的图像和文本符号的关系做了深入探讨，归纳了不同微课视频题材、体裁及微课中不同阶段过程中视觉符号间的作用和效果，同时指出了多模态话语的学科属性和与之匹配的思维结构之间的关系，为微课视频这一教育类多模态语篇的评析提供了新视角。

This article aims to initiate exploration into the multimodal academic discourse of micro-lessons in the blended-learning context. It develops a multimodal framework of the image-text relations in micro-lessons from Visual Grammar (Kress& van Leeuwen, 1996) and Systemic-Functional image-text relations theory (Martinec et al., 2005). The model is then used to establish evaluation criteria for communication effectiveness of two award-winning micro-lessons. Two principles are derived from the framework: (a) an equal status of image and text; (b) varied and appropriate logic-semantic relations between visual symbols. Through a detailed multimodal intersemotic analysis of the distinct micro-lesson videos, the genres and emphasis of each micro-lesson appear more evident. It is also found that the styles of these micro-lesson videos vary according to disciplines. Therefore, it is proposed that this multimodal framework should be useful for categorizing different genres of micro-lesson videos and giving sound evaluations to the communication effectiveness of most micro-lesson videos. Further studies on the audience’s perception of these videos are suggested.