The auxiliary bearing is applied to provide mechanical uphold for the rotational dropping rotor when contact event happens due to the active magnetic bearing (AMB) failure emergencies. During the rotor drop process, the auxiliary bearing will endure huge impact force and friction heat generation. The thermal behavior will affect the mechanical interaction and dynamic behavior of the auxiliary bearing and even induce rapid failure especially when excessive temperature growth occurs. The Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in China has proposed the 10 MW high-temperature gas-cooled reactor (HTR-10). It is designed to guarantee the inherent safety and economic competitiveness. The dry-lubricated ceramic auxiliary bearing is utilized to protect the AMB and aims to ensure the safety of the AMB system in the HTR-10 in the case of the special operational requirements in the reactor. This paper simulates the process of the rotor drop on the auxiliary bearings in the AMB system of the helium blower of the HTR-10, including the analysis of thermal growth based on the Hertzian contact model and a one-dimensional (1D) thermal heat transfer network model. The study results demonstrate the validation of the bearing models and elucidate different responses between mechanical and ceramic auxiliary bearings during contact events. The research in this paper offers important theoretical bases for the auxiliary bearing design to guarantee the safety of the whole system.