With the integration of the detailed text analytical model by Systemic Functional Linguistics (“SFL”, Halliday 1985) and the macro theoretical model of Critical Discourse Analysis (“CDA”, Fairclough 1989; 1995), this research analyzes three samples of SARS notices and theirtranslationsreleased in Macao by three different institutions during the Severe Acute Respiratory Syndrome (“SARS”) crisis in the first half of 2003. This study explores how the governmental institutions in the post-colonial society of Macao discursively constructed and reproduced their own positions, as well as how institutional power influenced the discursive production and reproduction (translation). Drawing upon the concept of interpersonal function in SFL, the writers conduct a comparative analysis of the SARS notices and their translations with a focus on speech roles, speech functions, modality types and modality orientation, the findings of which are interpreted from the perspective of CDA. Discussion based on the findings is carried on to explore how institutional power constructs discourse with particular institutional features through the configuration of linguistic recourses. It is hoped that this research only reveals the mechanism of how institutional power affects discursive production (/translation) but also offers a reference model for bilingual or multilingual text analysis in translation studies.