Abstract: Product quality can be an important factor to explain the formation of trade patterns and welfare outcome of trade liberation, which is testified by international trade theory and empirical results before the burgeoning of the “New-New trade theory”. However, quality heterogeneity within firms is needed to explain the new paradox excavated by micro-level trade data, acting as the corner stone of a new theoretical framework and econometric inferences. We surveyed those related theoretical and empirical articles. Theoretically, the introduction of product quality heterogeneity in static or dynamic framework，or endogenized product quality will be helpful to explain the paradox or new phenomenal in international trade, and empirically, it assists us to understand the firm behavior in export and the formation of trade pattern between developed countries and developing countries.
Key Words: Product Quality; Firm Quality Heterogeneity; Trade Pattern; Economic Growth
Journal of Zhongnan University of Economics and Law,No.1, 2015.( CSSCI, in Chinese)