Abstract: The traditional low-carbon economic dispatch only considers the issues of carbon emission sources, but does not consider the problems of carbon emission destinations. Therefore, based on the collaborative operation mode of carbon capture and power to gas（P2G）, while considering the carbon emission source and carbon emission destination at the same time, the concept of free carbon dioxide concentration（FCDC）is proposed. Because of the differences of carbon sinks in different ecological and geographical environments, considering the effects of atmospheric diffusion and ground vegetation carbon sink for carbon dioxide emissions, a FCDC distribution model is constructed. Then, the minimum average FCDC and the minimum total operating cost are used as the objective function to establish the optimal low-carbon economic dispatch model with carbon capture-P2G collaborative operation. Finally, the effectiveness of the proposed collaborative optimal dispatch model is verified by case simulation, which can reduce the carbon emissions while ensuring the economic benefits.