This study investigates the effect of thermal treatment on rockburst in granite caverns using true-triaxial compression tests on preheated granite samples with circular through-holes. The results show that the uniaxial compressive strength and elastic modulus of granite first increase and then decrease with temperature, reaching maximums at 200°C and sharply decreasing at 400–600°C. Density and P-wave velocity decrease, while peak strain increases with temperature. The main failure modes are X-shaped shear-tension failure at 25 and 200°C, and single-slope shear failure at 400 and 600°C. Thermal treatment has a slight effect on the rockburst incubation process, with the required stress for rockburst decreasing as temperature increases or decreases from 200°C. The mechanism of thermal treatment on rockburst involves the strengthening effect from water loss and the weakening effect from thermal expansion cracking. The study provides theoretical guidance for the stability analysis and rockburst prevention of temperature-affected granite caverns. The results indicate that thermal treatment has dual effects on rockburst, with the strengthening effect dominating at lower temperatures and the weakening effect at higher temperatures. The required stress for rockburst is highest at 200°C, and the rockburst intensity decreases with increasing temperature. The study highlights the importance of considering temperature effects in rockburst prevention for granite caverns.This study investigates the effect of thermal treatment on rockburst in granite caverns using true-triaxial compression tests on preheated granite samples with circular through-holes. The results show that the uniaxial compressive strength and elastic modulus of granite first increase and then decrease with temperature, reaching maximums at 200°C and sharply decreasing at 400–600°C. Density and P-wave velocity decrease, while peak strain increases with temperature. The main failure modes are X-shaped shear-tension failure at 25 and 200°C, and single-slope shear failure at 400 and 600°C. Thermal treatment has a slight effect on the rockburst incubation process, with the required stress for rockburst decreasing as temperature increases or decreases from 200°C. The mechanism of thermal treatment on rockburst involves the strengthening effect from water loss and the weakening effect from thermal expansion cracking. The study provides theoretical guidance for the stability analysis and rockburst prevention of temperature-affected granite caverns. The results indicate that thermal treatment has dual effects on rockburst, with the strengthening effect dominating at lower temperatures and the weakening effect at higher temperatures. The required stress for rockburst is highest at 200°C, and the rockburst intensity decreases with increasing temperature. The study highlights the importance of considering temperature effects in rockburst prevention for granite caverns.