In order to cope with climate change, accounting for carbon emissions from electricity consumption has become particularly important. A standardized carbon emission accounting system can, on the one hand, protect the rights and interests of users and mobilize enterprises to consume green electricity, and on the other hand, can systematically grasp the overall situation of carbon emissions from the national electricity consumption, and promote the whole society to realize low-carbon transformation. In this study, we propose a user-side electricity carbon emission accounting model based on the electricity transaction flow formed by user electricity transactions. The model has four modules, which are used to deal with user power activity data, regional carbon emission factors and dynamic adjustment, user power activity carbon emissions, and carbon offsets of user environmental interest products. The spatial and temporal resolution of the model can be accurate to the provincial day scale. This study also virtualizes the electricity consumption arithmetic example of a manufacturing enterprise in Guangdong, China, which shows that the model can well capture the total carbon emissions of the enterprise’s electricity consumption at different time scales and dynamically update the carbon emission factors. The example demonstrates that the model has a wide range of application potentials, which can more accurately account for user-side electricity carbon emissions, improve the spatial and temporal resolution of carbon measurement, promote the organic combination of the electricity market and the carbon market, and help China realize its dual-carbon goals.