Abstract: This study aims to investigate the effects of using gold tailings sand (GTS) as fine aggregate on the hydration behavior, microstructure, and mechanical properties of high-performance concrete (HPC). By using P.O 42.5 ordinary silicate cement, silica fume, fly ash, GTS, and standard sand, we designed GTS high-performance concrete (GHPC) specimens with different dosages of GTS. Testing methods such as uniaxial compression tests, splitting tensile tests, hydration heat tests, thermogravimetric analysis, and nuclear magnetic resonance were employed to systematically analyze the GHPC. The results show that the incorporation of GTS significantly enhances the early hydration heat release rate and maximum hydration emission heat of GHPC. Notably, at a dosage of 30.8% GTS, the most active reaction is observed after a 14-day curing period. The addition of GTS fosters the formation of hydration products, thereby improving the compressive and splitting tensile strength of the concrete. Furthermore, the judicious addition of GTS optimizes the pore structure of HPC, reduces porosity, and increases the proportion of cementitious pores while decreasing the proportion of non-capillary pores.