Abstract: The fracturing and movement of ultra-thick key stratum is prone to induce dynamic disasters, such as mine earthquakes and strong ground pressure. However, the damage and fracture evolution process remains difficult to investigate in depth because of limitations in experimental techniques and monitoring methods. Following the research paradigm of “method innovation — practical application — engineering verification,” this study systematically investigates the differences between carbon fiber similar-simulation composite materials and traditional similar-simulation materials in terms of electrical conduction mode and self-sensing damage capability. An electrical numerical model of carbon fiber composite material containing fractures was constructed, verifying the electrical response of the composite to the initiation and propagation of microcracks, and successfully applied to the simulation study of damage and fracture evolution in ultra-thick key stratum. Results show that doping carbon fibers changes the electrical conduction mode of the material from ionic conduction to electronic conduction. When the carbon fiber content reaches 2.00%, the electrical resistivity decreased by 92.5% compared with traditional similar-simulation materials. During fracture development and propagation, the resistivity change rate R_RC of the carbon fiber composite material and the damage factor D exhibit synchronous variation. For the same crack length, the variation amplitude of current density can reach 24.6 times greater than that of the traditional similar-simulation materials, enabling accurate monitoring of mining-induced crack development and propagation. Similar-simulation tests indicate that the damaged-fracture zone inside the ultra-thick key stratum follows a progressive evolution mode; in the early mining stage, rapid damage accumulation appears in the lower region of the stratum; the middle region shows accelerated growth of the damage factor after a certain mining width is reached; while the damage factor in the top region grows relatively slowly. Fiber-optic monitoring data show that the ultra-thick key stratum remained stable after mining two panels, the maximum height of mining-induced fracture development reached 347 m, extending to the middle region of the ultra-thick key stratum. This result is in high agreement with the progressive damage and fracture evolution law revealed by the physical simulation using carbon fiber composite material. The research results provide theoretical guidance for the prediction, early warning, and prevention of dynamic disasters in the overlying strata with ultra-thick key stratum above coal seam roof.