Abstract: Both English and Chinese linguists have conducted in-depth research on modal words considering the crucial role they play in interaction. Some of the research concerns modality in political news discourse, but the discourses this research focuses are in most cases merely in a single language. Comparative studies are rarely conducted. This paper, combining the systemic-functional linguistics and Chinese modality theory, modifies into a new theoretical framework and analyzes the Chinese and English modality system comparatively. A small corpus of twenty Chinese and twenty English political news texts from the perspective of modal orientation, modal values and modal types is built. The result of the research indicates: 1) In the aspect of modal orientation, modal words indicating subject implicitness and object implicitness are widely used in English and Chinese political news, and more modal words indicating subject implicitness can be found in Chinese political news. 2) In the aspect of modal types, modal words reflecting probability and inclination are widely used in English news while those indicating obligation and inclination are frequently used in Chinese news. 3) In the aspect of modal values, modal words with medium and low values are widely used in English news while those with high value are frequently used in Chinese news. These different choices of modal words conveyed various modal meanings.