Carbonation of recycled coarse aggregate (RCA) concrete was a complicated physical diffusion and chemical reaction process, which was difficult to analyze and predict. According to the carbonation mechanism of the RAC concrete, a multi-field coupled model for carbonation analysis of the RCA concrete was developed by combining the diffusion rule of CO₂ within the RCA concrete with the conservation law of mass for the carbonatable substances. The proposed model adopted effective diffusion coefficient of CO₂, coefficient of carbonation reaction rate, amount of carbonatable substances and adhesive mortar of the RCA as major control parameters. Efficiency and applicability of the proposed model were validated by comparing with experimental data.