Abstract: An automatic leveling type maintenance platform for a high-temperature gas cooled reactor is provided. A floating plate is automatically leveled by using a leveling liquid, and during leveling, only a water driving assembly needs to be controlled to drive a housing to be close to an inner bottom surface of a liquid storage groove, and a sliding block assembly and a lifting guide mechanism are controlled to be locked and fixed after the floating plate is leveled. In this way, complex and time-consuming fine adjustment control does not need to be performed, and the floating plate can implement automatic and rapid leveling and locking operation, so that a leveling effect is better. When the maintenance platform is used in a spherical top cap of a pressure vessel of the high-temperature gas cooled reactor for maintenance operation, support legs of a support assembly do not need to perform telescopic motion.