Abstract: The hydrostatic and hydrodynamic performance of a tilting pad journal bearing was experimentally investigated using on line computerized testing method and analyzing system, by variation of the load, rotating speed, and exciting force frequency. The tested bearing is an LBP four pad tilting pad journal bearing of diameter 152.15 mm and length to diameter ratio 0.703. The clearance ratio of the bearing is 0.0021, the static load applied on the bearing is 10 kN, 20 kN, 30 kN and 40 kN, respectively. The maximum rotating speed of the tested bearing is 6000 r/min, the ratios of the excitation frequency to the frequency of the rotating shaft range from 0.43 to 2.0. The magnitude of the excitation force is controlled to make sure that the tested bearing has a linear behavior in operation. Compared the measurement results with the theoretically calculated ones, it has been found that under different frequency of dynamic exciting force, the theoretically calculated dynamic coefficients of the tilting pad journal bearing are quite different from the experimental results. Under the operating condition of the tiling pad journal bearing, the theoretically calculated results are about one grade larger than the experimental ones. It has also been found from the experimental results that the variation of the excitation frequency has less effect on both stiffness and damping coefficients than that predicted by the theoretical method.