After calcination treatment, coal gangue exhibits good mechanical properties and has the potential to be fired into aggregates. This study investigated the effects of different ratios of coal gangue to feldspar, forming pressure and calcination temperature on the physical properties of aggregates, and analyzed the significance of each influencing factor using the grey correlation method. The microstructure and phase composition of the aggregates were explored using SEM and XRD. The results indicate that both the raw material ratio and calcination temperature significantly affect the physical properties of the aggregates. A high proportion of coal gangue reduces the liquid phase content and viscosity in the system, and the inability of gases produced during calcination to escape leads to the formation of more pores and microcracks inside the aggregates, degrading their mechanical properties. Increasing the proportion of feldspar powder and the calcination temperature promotes crystal nucleation. As potassium-sodium feldspar melts, the K⁺ and Na⁺ content increases and combines with [AlSiO₄] to form potash feldspar and plagioclase, promoting a dense internal structure of the aggregates. This study provides valuable insights for the precise utilization of coal gangue.