As one of the major sources of carbon dioxide emissions，the green，low carbon and sustainable development of China’s iron and steel sector is crucial for China to tackle the global climate change and achieve high quality economic development. Taking 18 Chinese typical iron and steel enterprises as examples，this study thoroughly analyzes their energy consumption，carbon dioxide emission performance and economic gains of carbon emissions trading. We find that the energy consumption and carbon dioxide emissions per unit of steel of 18 enterprises present an continuously downward trend over 2012-2019，which indicates that China’s iron and steel industry has made great progress in achieving low carbon development. In the meanwhile，the carbon dioxide emissions performance indicator of different enterprises is obviously different，and the average performance of 18 enterprises is approximately 0.562 in 2019，showing a slight increase compared with 0.558 in 2012. Besides，we find the carbon emission congestion phenomenon in 18 enterprises，which implies in a moderate carbon emission reduction may improve their productivity and output. Furthermore，we also find that carbon emissions trading among 18 enterprises is an effective way to reduce the economic cost of carbon emission reduction，and their total steel outputs present an obvious increase by implementing carbon emission trading，which could further improve carbon emission performance and reduce the emissions per unit of steel.