Abstract: Coal gangue (CG), a by-product of coal mining and processing, has long been considered problematic solid waste. Its large-scale disposal raises significant safety concerns and environmental issues. However, the current technologies for its harmless disposal and resource utilization remain inadequate. The performance of high-value CG products is suboptimal, market competitiveness is weak, and production costs are high. Additionally, the industry chain for high-value CG utilization is underdeveloped. To enhance CG resource utilization and improve environmental quality, developing effective treatment technologies has become an urgent priority for the coal industry. Calcination activation presents a promising approach to efficiently extract valuable elements and minerals from CG. However, a systematic understanding of the effects of calcination parameters on whiteness and pozzolanic activity of CG is still lacking. This study examines the effects of calcination methods, temperature, duration, heating rate, and particle size on the whiteness and pozzolanic activity of calcined CG products. By analyzing these factors, the study explores changes in the physical phase composition, micro-morphology, pore size distribution, whiteness, and pozzolanic activity of CG before and after calcination. Experimental results indicate that the optimal conditions for static calcination are a temperature of 900 °C, a duration of 2 h, and a heating rate of 30 °C·min^–1. For dynamic calcination, the optimal conditions are a temperature of 900 °C and a duration of 2 h. The highest unit calcium absorption observed for the static calcined product is 1132.00, while for the dynamic calcined product, it is 1295.52. The dynamic calcined products exhibit superior whiteness and pozzolanic activity when compared to static calcined products. However, within the temperature range of 600–900 °C and a calcination time of 2 h, the whiteness of static calcined products increases more significantly than that of dynamic calcined products. Unlike dynamic calcination, the whiteness of static calcination continues to improve with prolonged calcination time. Additionally, dynamic calcination minimizes sintering effects and enhances the specific surface area and pore structure characteristics of the calcined products. With extended calcination time, the whiteness of calcined products continues to improve. Under identical calcination conditions, products with smaller particle sizes exhibit higher whiteness and pozzolanic activity. Dynamic calcination also effectively enhances the pozzolanic activity of CG. The heating rate and calcination time influence the degree of dehydroxylation of kaolinite, thereby affecting the pozzolanic activity of the calcined products. Furthermore, calcination methods impact heat transfer efficiency, oxygen diffusion, and decarbonization efficiency. This study provides theoretical and technical guidance for the high-value utilization of CG.