This study aims to compare the rhetorical move structure of English Medium Instruction (EMI) lectures given by native English and Chinese lecturers. Two specialized corpora were therefore accordingly created with transcripts of twelve science-oriented lectures selected from MICASE and the BASE corpus and twelve science-oriented EMI lectures collected at a Chinese university, respectively. Adopting the Swalesian genre analysis framework, this study examines the moves/steps of EMI lectures in the two corpora. Then, the conventionality and frequency of moves/steps were quantified and analyzed to capture statistical variations. In addition, semi-structured interviews were conducted with four Chinese EMI lecturers to probe into their discursive practices from an emic perspective. Statistical variations were apparent in several moves and steps, which could be mainly attributed to Chinese EMI lecturers' concern for the program quality, dense course syllabus requirements, a lack of specific English for EMI teaching, as well as the emergence and influence of new social media. The study argues for well-targeted teacher training for non-native English lecturers and more teacher autonomy in course syllabus design.