In order to establish a prediction method for the minimum oil film thickness of tilting pad thrust bearing during idling,based on the actual working conditions of the thrust bearing of the nuclear main pump and the self compiled program of Reynolds equation,the calculation and numerical simulation analysis of the lubrication performance parameters of the main and auxiliary bearing pads under hot and cold conditions were carried out,and the theoretical formula for the minimum oil film thickness of tilting pad thrust bearing was proposed.The calculated minimum film thickness was compared with the theoretical value.The results show that with the decrease of the rotating speed,the minimum film thicknesses of the main bearing pad monotonically decreases,while the minimum film thickness of the auxiliary bearing first increases and then decreases.The calculated minimum film thickness of the main and auxiliary bearing pads can correspond well with the fitted values,verifying the reliability of the theoretical fitting formula.The theoretical fitting formula can predict the minimum oil film thickness under various working conditions through the calculation results of minimum oil film thickness at rated speed,which provides an important reference for the safety of the idling of the main pump.