Prefabricated cabin substations, as a new type of substation, have advantages such as saving investment, a short construction period, and low-carbon environmental protection. They are the mainstream development trend of low-carbon substations in the future and play an important role in the construction of new power systems, especially in the development of urban power grids. This article systematically conducted carbon footprint tracing, analysis, calculation, and evaluation of prefabricated substations during the planning, construction, operation, and scrapping stages, forming a carbon footprint accounting method for the entire life cycle of prefabricated substations. The research results show that the carbon footprint of the construction and operation stages accounts for more than 90% of the carbon footprint of a prefabricated substation throughout its life cycle. Material carbon footprint, SF6 carbon footprint, and station electricity carbon footprint are important components of the substation’s carbon footprint. Green plants and lawns can effectively reduce the carbon emissions of prefabricated substations and have a positive effect on controlling carbon footprints. Suggestions were put forward to reduce the carbon footprint of prefabricated cabin substations in the areas of equipment replacement, energy conservation and consumption reduction, operation monitoring, and optimization. Simultaneously, carbon footprint prediction models for substations based on the bat algorithm (BA) and extreme learning machine (ELM) were constructed to accurately predict the carbon footprint of substations at various stages, providing a reference for the design selection, scheme optimization, energy-saving, and carbon reduction transformation of prefabricated cabin substations.