ABSTRACT Speech roles and modality are important linguistic aspects that reveal interpersonal relationship between an addresser and his/her addressees. However, speech roles and modality have not been much studied in the context of translation studies, especially with regard to translation shifts in speech roles and modality in different types of texts. Therefore, by analyzing English texts and their Chinese translations in legislative and business areas in terms of speech roles and modality, we attempt to find a key to better understanding translation shifts in such respects and the effects they achieve. Hallidayan systemic functional grammar is adopted as the theoretical framework for this study. The analysis of the translation shifts in our sample shows that different types of texts exhibit different degrees and scales of probabilities, authority, obligations, and inclination with regard to speech roles and modality. No shift is observed in the translation of legislative texts, while significant shifts are found in the business promotion texts. In addition, we find that the shifts of speech roles and modality in the business promotion texts tend to relate to various factors, especially differences in the interpersonal relationship between English-speaking and Chinese-speaking social contexts. Keywords: speech roles, modality, translation shifts, systemic functional grammar, interpersonal relationship, legislative, business