Abstract: As the heart of the gas turbine, the central rod-fastened rotor operates under harsh conditions with frequent incidents, necessitating a rigorous exploration of its strength under complex contact states across multiple scales and loads to ensure the safe functioning of the disc structure. Employing a rough surface contact model and three-dimensional finite element methods, a thermo-mechanical coupling analysis model for the gas turbine disc’s Hirth tooth contact interface was developed, incorporating microscale interface dimensions and surface roughness. Results show that the maximum equivalent stress of the end face teeth decreases with the increase of the root fillet radius and the decrease of the pressure angle; the maximum equivalent stress and average contact pressure of the end face teeth decrease with the increase of surface roughness.