Radar and infrared compatibility stealth at high temperature is difficult to achieve due to their opposing mechanism. Meanwhile, stealth structures are required to experience thermal insulation and load-bearing performance due to the high-temperature harsh environment and high velocity thermal airflows impacts. Currently, few materials can satisfy the above demands simultaneously. Herein, a ceramic matrix lattice sandwich metastructure with high-temperature radar infrared compatibility stealth characteristics, thermal insulation, and load-bearing capacities was exploited through the crossover design of electromagnetics, mechanics, and thermodynamics. A square lattice sandwich structure was constructed through interlocking technology with the rivaling out-of-plane compressive strength. The electromagnetic wave absorption property of metastructure is designed and optimized according to the equivalent circuit model based on the electrical loss theory. The metastructure exhibits excellent −10 dB absorption bandwidth at 800 °C of 4.5–14.8 GHz. Furthermore, the metastructure achieves infrared stealth at high temperature by reducing the surface temperature (from 1150 °C to 362 °C) of objects through gradient distribution structure. The lattice sandwich metastructure proposed here is expected to aid in the creation of advanced high-temperature multifunctional stealth materials.