Abstract: The life cycle carbon metering and carbon trading mechanism can fully reflect the concept of green and coordinated development, which holds great significance for guiding the low-carbon construction of microgrid system. Aiming at improving the economic and environmental benefits of microgrid, in this paper we propose a multi-objective capacity optimization configuration model in microgrid with life cycle carbon metering and carbon trading mechanism taken into account. Firstly, based on the typical microgrid system architecture, we examine the carbon emission of each equipment by using the whole life cycle method. Additionally, we introduce the carbon trading mechanism to the system and constructs a carbon emission metering and carbon trading mechanism for the microgrid system. Secondly, a multi- objective configuration model is established for microgrid system capacity optimization, with the goal of minimizing both the present total costs and the carbon emissions throughout its entire life cycle. Finally, we utilize the typical daily data from a specific operational power grid as an example for analysis. The results indicate that the model can effectively improve the economy of the microgrid system under the premise of reducing carbon emission as much as possible.