when post-earthquake reconstruction carbon emission is high it would have a significant environmental impact. Therefore, it is necessary to propose a monitoring method of carbon emission for civil building reconstruction after the earthquake. To solve the problems of inaccurate monitoring results and low monitoring efficiency in the existing monitoring methods of carbon emission in civil building reconstruction after the earthquake, a new approach was proposed in this work. First, the carbon emission basis was elaborated in detail, and the research was carried out in compliance with the international carbon emission standard. Second, the emission coefficient method was used to complete the data collection of building carbon emissions. Based on the boundary conditions of carbon emissions in the building use stage, the boundary conditions for carbon emissions were determined. Finally, the carbon emission of reconstructed civil buildings after the earthquake was calculated, and the carbon emissions monitoring was done in real-time. The experimental results showed that the proposed real-time monitoring method can effectively monitor the carbon emissions of post-earthquake reconstructed buildings, and has a high monitoring efficiency.