Abstract: Exploiting the electricity-carbon coupling value and establishing an electricity-carbon synergistic market are important means for achieving carbon peak and carbon neutrality targets. The coupling of electricity carbon information relies on a reasonable and effective electricity carbon measurement system. However, the current electricity carbon measurement system still needs to be improved. It is difficult to fully clarify the carbon emission responsibilities within electricity trading behavior. Facing the above challenge, this paper proposes a new electricity carbon metering method considering the electricity trading behavior and based on the theory of carbon emission flow. First, the actual lossy network is equivalent to a lossless network considering the calculation characteristics of the carbon emission flow theory. After that, the transaction electricity and non-transaction electricity flow are disassembled, and their carbon emission responsibility is independently measured according to their electricity sources. This method strictly abides by the principle of direct and indirect carbon emissions balancing, and it can clarify the transfer of carbon emissions responsibility behind electricity trading behavior. Also, the spatial and temporal differences in carbon emission factors can be reflected by this method, and it has the ability of leading low-carbon demand response. Based on operation profiles from the PJM-5 bus system and the power system of a city in China, the simulation analysis is carried out. The simulation results verify the effectiveness of the method.