Abstract: The construction industry is the main steel consumption field in China.As the most consumed basic raw material, steel has entered the economic and social development in large quantities.At present, the stock of steel in China’s building construction has reached a large scale.Systematic understanding of the steel stock and life cycle in building construction has guiding significance for the rational use of future scrap steel.This paper takes the Yangtze river delta as a case study and based on the dynamic material flow analysis, the paper also estimates the historical evolution of steel stocks in building construction in the region since 1949.The results show that in 2016, the total steel stock in building construction in the Yangtze river delta region reached 677 Mt, among them, Jiangsu 46%, Zhejiang 29%, Anhui 16%, Shanghai 9%.From the perspective of steel stock per unit area, Shanghai 9 370 kg/m², Jiangsu 3 024 kg/m², Zhejiang 1 929 kg/m², Anhui 796 kg/m².