In academic English writing, research on lexical bundles is of great importance. This paper takes English abstracts from engineering journals as the subjects and applies a corpus-based analysis to explore the differences of most frequent 3-word lexical bundles commonly used by native speakers and Chinese learners. It focuses on the influences of lexical structures and lexical functions on Chinese writers in different moves. The results show that there exists a significant difference in the frequencies of the total and the individual lexical bundles. It is also found that lexical structures and functions are the important factors affecting the use of lexical bundles in different moves, and there is a significant correlation between them. The findings have some implications for second language acquisition and academic writing pedagogy.