Ceramic coating materials own some advantages, for example high-rigidity, good abradability and good performance under high temperature. At the same time, ceramic coating materials are also difficult-to-machine materials. High machining precision and efficiency can be obtained in grinding WC-Co coating by cup wheel. The affection of grinding temperature is very important for grinding processing. But there is no research on grinding temperature of WC-Co coating by cup wheel. So in this paper, grinding temperature by cup wheel is researched on theory, the new concept, which is effectiveness width of arc moving heat source, is presented, and theoretical formula of grinding temperature is also built. Then experimental research on grinding temperature of WC-Co coating by cup wheel is done by use of thermocouple temperature measurement technology. The experimental results show the validity and effectivity of the theoretical formula. The affection of grinding parameters to grinding temperature is researched also.