Abstract: Urban rail transit projects consume a substantial amount of energy and generate significant quantities of solid waste and carbon dioxide during their construction and operation. It is imperative to address carbon emissions in urban rail transit projects without delay. This study drew upon research achievements on carbon emissions from urban rail transit projects, both domestically and internationally, and identified the three primary factors that influence carbon emissions in such projects:economy, technology, and institutions. Twelve factors, including fixed asset investment in urban rail transit, maturity of low-carbon technologies, and stringency of environmental regulations, were selected as observable indicators. Then a survey questionnaire was carefully designed to conduct empirical research. By employing the partial least squares structural equation model, we analyzed the causal pathways and impacts of these influencing factors on carbon emissions in urban rail transit projects. The research found that both economic systems and technological factors have significant impacts on the carbon emissions of urban rail transit projects (0.433, 0.317, 0.224). Therefore, achieving carbon reduction in urban rail transit projects requires the joint participation of economic systems and economic factors. Moreover, economic factors have a significant influence on both systems and technologies (0.748, 0.514). Therefore, it is important to focus on increasing investment in economic elements to achieve carbon reduction in urban rail transit projects. Moreover, we provide actionable recommendations, with significant reference value for achieving energy efficiency and emission reduction in urban rail transit systems.