In this paper, based on the Cobb-Douglas function including the technical progress, the relationship between industri- al structure and economic efficiency in Hengyang city is examined by selecting regional specialization and diversification, (Theil entro- py), industry level ( the proportion of the third and the second industry) as a measure of industrial structure. The data come from China City Statistical Yearbook between 2004 and 2014. The result shows that: at present, economic growth of Hengyang is mainly driven by investment; With r...