On-line monitoring method of structural characteristics and traditional performance parameters of babbitt metal pad thrust bearing is analyzed. Based on deformation characteristics of elastic metallic plastic(EMP) pad thrust bearing, an oil film thickness measuring system is applied to set up a new kind of optical fiber reflective sensor model, the outputs of the sensor are independent of the characteristics of the light source, the losses in the ambient medium and the target reflectivity. Additionally, the distance information is averaged over several points on the target surface, which reduces signal fluctuations due to inhomogeneities. An optical fiber sensor model of correcting static error based on BP artificial neural network (ANN) is set up also. According to the actual operation in thrust bearing test board, the designed system shows better performance.