This contrastive study is concerned with relations between rhetoric and ethnicity in second language (L2) writing. It investigates the influence of Chinese rhetoric on expository writing in English by three groups: the majority Chinese Han group, and two ethnic minorities, Tibetan and Mongolian. Relying on a contrastive text analysis of 30 hortatory exposition texts (10 for each group), the study critically examines the generic and rhetorical structures of the three groups' writing. The written outputs of the three groups are discussed with reference to Chinese EFL writing as a whole, and differences and similarities are identified and discussed. It is found that while the Tibetan, the Mongolian and the Han samples are similar in some general respects, they nevertheless differ from one another in a subtle manner, for example, in generic structure and the use of Qi-cheng-zhuan-he structure sequences within/between discourse units. These findings might result from mainstream Chinese culture's overriding influence on the rhetoric of the two subcultures. The study concludes by suggesting that future intracultural contrastive studies be carried out with consideration of students' first language (L1) transfer, English proficiency and learning experiences, and other developmental factors.