<p>The insulation failure of synchronous generator winding is usually the early cause of short circuit fault, especially under the combined action of electromagnetic force, thermal stress and mechanical stress. This paper comprehensively investigates the mechanical–thermal response characteristics of end-winding insulation under different rotor interturn short circuit (RISC) positions in synchronous generators. Based on the magnetic–thermal–solid coupling model, not only are magnetic flux density and electromagnetic forces obtained in the stator end-winding region, but also the dynamic characteristics of deformation, stress, and strain in the winding insulation are separately calculated. Furthermore, weak locations of stress and strain concentration in the winding are identified. The entire work is grounded in qualitative theoretical analysis, finite element analysis, and experimental verification. The result shows that RISC results in non-uniform stress and temperature distributions of insulation materials, which will significantly increase the mechanical–thermal response of the winding insulation material, and aggravate the deformation, stress and strain of the insulation material. The stress at the joint and nose end of winding insulation is significantly higher. These specific locations are the dangerous point of winding insulation failure.</p>