Nuclear main pumps,water turbines and other equipment are mostly vertical shafting,and the thrust bearings in the shafting are fan-shaped tilting pad bearings.Considering the thickness of the lubrication film from the perspective bearing capacity and anti-wear,the thickness of the lubrication film becomes an important indicator to reflect and characterize the working state of thrust bearings.In order to accurately detect the lubricating film thickness of tilting pad thrust bearing,a detection model for lubricating film thickness was presented based on ultrasonic nondestructive testing technology,an ultrasonic detection system for lubricating film thickness of thrust bearing lubrication film was constructed,which was mainly composed of a test bed for thrust bearing and an ultrasonic online detection device.Under the condition that the rated speed of thrust bearing is 1 800 r/min and the test time is 6 min,the value of lubricating film thickness near the oil inlet and outlet edges of the thrust pad was obtained by ultrasonic testing,and the value of lubricating film thickness at the fulcrum of the thrust pad was obtained by eddy current testing.The ultrasonic testing value was compared with the corresponding theoretical calculation value.The calculation value of lubricating film thickness based on ultrasonic testing is 47 μm,and there is only a difference of 4 μm compared with the average lubricating film thickness of 51 μm measured by eddy current sensor,which validated the feasibility of ultrasonic testing method from the prospect of experiment.Furthermore，there is only a 8 μm difference between the theoretical and ultrasonic values of lubricating film thickness at point 1,and a 3 μm difference between the theoretical and ultrasonic values at point 2,which validated the feasibility of ultrasonic testing method from the prospect of theory.