Abstract: The digital twin technology, utilizing the high-precision virtual modeling and the real-time data acquisition, plays a crucial role in the design, operation, and maintenance of high-temperature components. Robust, sensitive and stable sensors are indispensable for precisely characterizing the operational status of these components. The dense amorphous SiCN ceramics was fabricated through liquid molding of the polysilazane (PSN1) precursor, and the pyrolysis temperature effects on the microstructural evolution, the micro-nano mechanical properties and the piezoresistive response were investigated. The results demonstrate that, with the increase of the pyrolysis temperature, the amorphous SiCN density and the structural free carbon phase degree of order will gradually rise. Within the pyrolysis temperature range of 1 000~1 200 ℃, the density increase as the dominant factor markedly augments the elastic modulus, the hardness, and the creep index. At a temperature up to 1 300 ℃, the free carbon structure orderliness as the dominant factor enhances the deformation ability of the amorphous SiCN, resulting in decreases of the elastic modulus, the hardness and the creep index. Furthermore, the orderliness of the free carbon conducting phase significantly promotes the electrical conductivity of the amorphous SiCN. The amorphous SiCN subjected to pyrolysis at 1 300 ℃ exhibits the highest piezoresistivity coefficient (310~416), and the corresponding electrical resistance value shows a sharp drop trend followed by a gradual flattening with the stress. The amorphous SiCN still exhibits excellent piezoresistive performances and stability at a high temperature up to 900 ℃, promising a potential application in the field of high-temperature pressure sensors.