A terahertz graphene patch-type high-temperature sensor is designed to solve the problems of the small temperature measurement range, large size, and low sensitivity. The sensor is composed of a hexagonal graphene film, an alumina substrate, and a three-layer gold structure. The characteristic size of the terahertz MEMS high temperature sensor with large range and high sensitivity is obtained by optimizing the graphene structure size and alumina substrate thickness. The results show that the temperature sensor can measure temperatures ranging from 25 ℃ to 1 050 ℃ in a frequency range of 3.0~5.0 THz, with a sensitivity of 0.259 GHz/℃ and an overall volume of 20 μm×21 μm×14.5 μm. The sensor has excellent sensing performance and a wide temperature range, allowing it to provide a technical method for measuring the temperature of an aero-engine, rocket launch system, or harsh environment monitoring system in a high temperature environment.