Coronavirus (COVID-19) has caused more than millions of death globally. All sorts of media are of significant concern about current news, perceptions, and opinions on the pandemic. It is found that Chinese news reports focused on describing the Chinese government's attitude and measures in response to the COVID-19 pandemic, and the wording was objective and neutral. However, the American media adopts language strategies, and the low modality value in the report content is used more frequently, with uncertainty. Part of the word selection is non-neutral. The different social cultures of China and the United States, China's rising international status, and the U.S. election are all crucial factors affecting news discourse on the outbreak. Based on a self-built small corpus, this paper combines the two dimensions of the vocabulary classification system and the systemic functional grammar modal system to compare and analyze the Chinese and American mainstream media reports on the COVID-19 pandemic. The article explores news discourse and the ideological differences behind it and examines the reasons behind it.