Covid-19 brings about many researches on pandemic discourse. Based on the theoretical framework of Multimodal Discourse Analysis construed，this study tends to explore the multimodal representations in the articles on COVID-19 prevention published on the website of World Health Organization. This research finds that on the website of World Health Organization，there are various forms of scientific knowledge representation modes in the articles on epidemic prevention suggestions，including verbal modes，visual modes and sensory modes. Among these modes，verbal representations are dominant，with visual representations and sensory representations functioning as enhancement.