Over the past few decades there have been extensive empirical and theoretical studies of the determination of intra-industry trade (IIT), but mostly for the industrialized countries. This paper aims to assess the trends and pattern of intra-industry trade and structural adjustment in China's manufacturing sector associated with its trade liberalization using data spanning from 1990 to 2000. In particular, we distinguish intra-industry trade as either horizontally or vertically differentiated, and examine how the various country-specific factors affect the intensity of China's horizontally and vertically differentiated intra-industry trade with its major trading partners, and how trade liberalization changes the pattern of China's IIT and integration with the East Asian region. These issues have important policy implications for product differentiation strategy and labour adjustment. Copyright © 2006 John Wiley & Sons, Ltd.