Abstract: The purpose of this paper is to study the thermal behavior of a tilting-pad journal bearing subject to a sudden dynamic load.The time-dependent Reynolds equation and energy equation were used to analyze the transient pressure and temperature of the oil film during this period.The dynamic equations were developed to simulate the motion of journal and pads.These equations with initial conditions were solved numerically using finite differential methods and the Newton-Raphson iterative scheme simultaneously.The nonlinear thermal transient response of tilting-pad bearing was simulated under a step load function.The change of maximum film temperature and minimum film thickness as well as other parameters were presented.Oil film temperatures and film thickness were found to vary considerably, and there existed some overshoot in the responses of maximum temperature and minimum film thickness, leading possibly to the damage of bearing during the transient period.