<p>As the grade of mineral resources continues to decline and production costs rise, increasing attention is being paid to ore sorting technologies, aiming to enhance the feed grade entering the crushing, grinding, and beneficiation stages, reduce the ore throughput in downstream processing chains, and improve overall efficiency. Microwave infrared (MW-IR) has been proposed as an excitation–discrimination technique for developing a novel ore sorting method. Consequently, understanding the thermal contrast of ore and waste rock after microwave heating is particularly critical. Microwave heating experiments were conducted under varying process conditions, including microwave power, heating duration, and sample size. The surface temperature distribution characteristics, non-uniformity, and the thermal contrast between ore and waste rock were analyzed. The results showed that both ore and waste rock exhibited pronounced temperature non-uniformity after microwave exposure, with evaluation indices differing by several to tens of times. Significant variation was also observed across different surfaces of the same sample in parameters such as maximum temperature, average temperature, temperature range, temperature non-uniformity index, and coefficient of variation. Notably, microwave power and heating time did not alter the temperature distribution trend on the same surface, while the effect of sample size on non-uniformity indices of ore and waste rock exhibited the opposite trend. Moreover, no significant correlation was found between the permittivity at different locations on the ore surface and the temperature distribution. It is recommended that numerical simulation methods are employed to investigate the factors influencing temperature distribution. These findings offer important insights into the distinct thermal responses of ore and waste rock to microwave heating and provide a scientific basis for advancing MW-IR-based ore sorting technology.</p>