The flash temperature in the sliding frictional contact between micro-asperities has an important influence on the frictional characteristics of advanced functional ceramics. In this paper, the elastic sliding frictional contact of a three-dimensional micron/submicron scale asperity pair is considered. A three-dimensional finite element model (FEM) for fully coupled thermal-stress analysis of sliding contact of SiC/Al2O3 asperity pair is developed. An empirical correction factor for contact characteristics is obtained based on the FEM results. The FEM results show that, compared with the Hertz theoretical solution, the contact area becomes smaller and the contact pressure becomes larger in the case of sliding contact with large deformation. The flash temperature has a negative correlation with the composite radius of the asperity pair and a positive correlation with the interference depth and sliding speed. Using Hertz theory, a parabolic distributed heat source, the Fourier heat conduction law, and the newly proposed correction factor, a semi-analytical model of flash temperature during the elastic frictional sliding between two single asperities is established. The relative difference between the flash temperature predicted by the established semi-analytical model and the FEM model is less than 1.2%. The relative difference decreases with the increasing interference depth. This work is a valuable reference for studying the frictional heat-related issues of advanced ceramics.