Abstract: Corpus-driven method has become the main stream in lexical chunk research. The quantitative and qualitative data have laid bare Chinese Science and Engineering Collegians' use of ten structural types of lexical chunks from systemic-functional perspective. The data shows that subjective-predicative chunks and predicative verbal chunks compose the main ingredients of conversation. Learners use more mental process verbal chunks, declarative speech and interpersonal idioms, but narrower Range and Goal, overlapped Theme and Given and simplex cohesion. Overall speakers' oral discourse bears natural and interactive features with distinct spoken register.