<p>The precise acquisition of in situ mechanical parameters for deep rock constitutes a critical challenge. Traditional experimental methods have shortcomings in terms of micromechanical characterization and applicability in high-temperature environments. To overcome these limitations, a multiscale framework integrating nanoindentation experiments and GPU-accelerated molecular dynamics (MD) simulations was established to quantify temperature-dependent dislocation evolution in deep sandstone. By integrating nanoindentation experiments, X-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and scanning electron microscopy (SEM) coupled characterization techniques, we systematically analyze the rock mineral composition and micromechanical properties. Furthermore, a molecular dynamics model is constructed to simulate the nanoindentation process and mechanical response under high-temperature conditions. Under nanoindentation, the plastic deformation of rock undergoes a dynamic process consisting of dislocation nucleation, slip, and three-dimensional propagation; atoms in the shallow layer are dominated by plastic deformation, whereas those in the deep layer exhibit significant elastic recovery. High-temperature environments cause the elastic modulus of rock to decay exponentially with increasing temperature, and the hardness nonlinearly decreases with increasing temperature. Concurrently, dislocation recombination and crack healing mechanisms significantly suppress stress concentration, promoting a transition in rock mechanical behavior from brittle to ductile. These findings provide a multiscale analytical framework for assessing the in situ mechanical performance of rock in deep oil/gas reservoirs and geothermal engineering, offering significant theoretical guidance for resource exploration and development design in complex temperature environments.</p>