Abstract: ［Objective］ By studying the carbon footprint of two kinds of side wallboard made of different materials for rail vehicles, the accounting method for the carbon footprint of interior products is explored to guide designers in achieving low-carbon design. ［Method］ Side wallboards made of PC (polycarbonate) and FRP (fiberglass-reinforced plastic) for rail vehicle interiors are selected as research objects. Following the lifecycle assessment method outlined in PAS 2050:2011 ′Specification for the Assessment of the Life Cycle Greenhouse Gas Emissions of Goods and Services′, published by the British Standards Institution, the carbon footprints and contributions of the two different materials′ side wallboards at each lifecycle stage are calculated. ［Result & Conclusion］ Within the defined system boundaries, the carbon footprint of FRP side wallboard is greater than that of PC one, with the highest contribution to the carbon footprint observed during the raw material acquisition stage for both types of wallboards. Under the premise of meeting vehicle performance requirements, selecting PC side wallboards with a lower carbon footprint is more conducive to overall vehicle decarbonization.