Abstract: Stone mastic polyurethane concrete (SMPC) is a novel pavement material that completely replaces asphalt with polyurethane as the binder. To accurately evaluate the variation of SMPC pavement performance with polyurethane to aggregate ratio, different methods including laboratory test, microscopic test and mathematical statistical analysis were employed in this study. Firstly, the curing process of the polyurethane binder was initially analyzed by Fourier transform infrared (FTIR) Spectroscopy to determine the time required for strength formation in SMPC. Afterwards, considering the different polyurethane to aggregate ratios after curing, a series of tests on high-temperature performance, low-temperature performance, and moisture susceptibility of SMPC were conducted. Subsequently, relationship models of SMPC pavement performance were established by using grey system theory. The results revealed that after seven days of reaction, the isocyanate (—NCO) group in polyurethane disappeared, indicating that its binder strength was completely formed. Under the condition of normal mineral powder consumption at 10% weight of SMPC, the high-temperature performance, low-temperature performance, and moisture susceptibility of SMPC all exhibited significant reductions as the polyurethane to aggregate ratio decreased. It is also found that the high-temperature performance and moisture susceptibility of SMPC could be improved by increasing the amount of mineral powder. Finally, relationship models for SMPC's dynamic stability, bending strain at failure state, and freeze-thaw splitting strength under different polyurethane to aggregate ratios were established by using grey system theory, elucidating the connection between pavement performance and polyurethane to aggregate ratios.