Under the background of the global "dual carbon" strategy, Recycled Asphalt Pavement (RAP) has become a core path for low-carbon development in road engineering due to its ability to reduce carbon emissions from the extraction and production of new raw materials. Currently, the life cycle assessment (LCA) model is the mainstream method in the carbon emission assessment models of recycled asphalt pavement because it covers the entire chain from "raw material acquisition - recycled production - construction - use and maintenance - disposal". However, it has limitations such as insufficient data standardization, weak dynamic correlation, and insufficient analysis of parameter coupling mechanisms. This paper reviews the application progress of LCA in this field, which has gone through three stages: "partial accounting - multi-dimensional integration - dynamic optimization", and it is necessary to combine scenarios and divide the carbon emission scope according to the "IPCC National Greenhouse Gas Inventory Guidelines" to improve the adaptability of accounting. At the same time, it analyzes the influence of raw materials and dosage, recycling process types, process factors, and external factors on carbon emissions, clarifies key parameters such as the optimal RAP dosage of 60%-80% and the suitable temperature of warm-mix technology of 120-130℃, and also points out problems such as the lack of basic emission data and differences in LCA software calculation results. In addition, it analyzes the degree of influence of each parameter, with the recycling process type having the highest influence weight (35%-40%), followed by the RAP dosage (25%-30%), and there are "synergistic gains" and "offset losses" phenomena in multi-parameter coupling. Finally, it summarizes the emission reduction advantages and key control variables of recycled asphalt pavement, and proposes future directions such as building an LCA standardization system and strengthening research on new technologies, providing references for the low-carbon transformation of the industry.