To lift the longitudinal section of existing bridges in highway reconstruction and expansion projects due to insufficient under-bridge clearance, this study took the reconstruction of a 32.5 m T-beam bridge in the reconstruction and expansion project of the Guangzhou?Shenzhen Expressway as the research object. By using a carbon emission factor method, carbon emissions of three reconstruction schemes, including broken-column jacking, conversion of bearing pads into bridge piers, and demolition and reconstruction, were calculated under different lifting heights, and the corresponding construction and installation costs were compared. The results show that when the longitudinal section of the bridge is lifted to a certain height, the economic benefits of the broken-column jacking and the demolition and reconstruction schemes are basically equivalent, but the total carbon emissions of the jacking scheme are significantly lower than those of the demolition and reconstruction scheme. In the broken-column jacking scheme, the carbon emissions from material production, off-site transportation, and direct construction account for 86%, 2%, and 12%, respectively. This indicates that material production is the main source of carbon emissions, followed by construction machinery. The jacking renovation scheme not only conforms to the “carbon peak and carbon neutrality” policy in China but also achieves equivalent economic benefits to the demolition and reconstruction scheme under certain conditions. The research findings can provide a reference for the decision-making of bridge jacking project schemes.