China announced its promise on CO2 emission peak. When and what level of CO2 emission peak China's primary aluminum industry will reach is in suspense. In this paper, a system dynamic model is established, with five subsystems of economy development, primary aluminum production, secondary aluminum production, CO2 emission intensity and policies making involved. The model is applied to examine potential CO2 emission trends of China's primary aluminum industry in next fifteen years with three scenarios of "no new policies", "13th fiveyear plan" and "additional policies". Simulation results imply that: merely relying on rapid expansion of domestic scarps recycling and reuse could not mitigate CO2 emission continuously. Combination of energy saving technology application and electrolytic technology innovation, as well as promoting hydropower utilization in primary aluminum industry are necessary for long term low-carbon development. From a global prospective, enhancing international cooperation on new primary aluminum capacity construction in other countries, especially with rich low-carbon energy, could bring about essential CO2 emission for both China's and global primary aluminum industry.