This study explored the differences in high school students' scientific epistemological beliefs (SEBs), motivation in learning science (MLS), and the different relationships between them in Taiwan and China. 310 Taiwanese and 302 Chinese high school students' SEBs and MLS were assessed quantitatively. Taiwanese students generally were more prone to believe that scientific reality is invented, the development of scientific knowledge is culture-dependent, and scientific knowledge is always changing and its status is tentative than the Chinese students were. Yet, the Taiwanese students perceived higher test anxiety in science than the Chinese students did. Moreover, Chinese students who have a stronger belief that science knowledge is changing and tentative are more likely to perceive themselves as having higher test anxiety in science. The results suggest that the role of culture might have an impact on students' SEBs and their MLS. (Contains 5 tables.)