Abstract: The wedge-shaped oil film in sliding bearings induces uneven heating effects on the journal of a rapidly rotating rotor, resulting in circumferential temperature variations in the journal. The thermal bending caused by these temperature differences exacerbates rotor vibration, leading to a phenomenon known as "Morton effect" or rotor thermal instability. This effect is particularly severe in cantilevered rotors. Initially, an elliptical bearing's thermal fluid lubrication model is established, and its dynamic coefficients and oil film temperature field are calculated. Subsequently, based on Fourier heat conduction theory, using the obtained oil film temperature as a boundary condition, a finite element method is employed to solve the three-dimensional transient temperature field of the journal to determine the thermal deformation and thermal stress. The thermal stress is then integrated to obtain an equivalent moment for rotor dynamic analysis. Additionally, the sliding bearing oil film thickness is updated based on thermal deformation. Repeating these steps completes the fluid-solid-thermal multi-field coupling analysis of the rotor-bearing system, and the effectiveness of the simulation model is validated against experimental data. Finally, parameter analysis is conducted on the rotor-bearing system with the rotor's cantilever length and suspended mass as variables. The results indicate that reducing the cantilever length or decreasing the suspended mass effectively reduces system vibration.