Abstract: [Objectives] In order to analyze the dynamic and tribological characteristics of the main bearing of an engine and the coupling relationship between them. [Methods] The dynamic model of the Sapphire bearing test machine is established by using dynamic substructure method, and the result is verified on the test machine. On this basis, the coupling analysis of the tribology and dynamics of the bearing is carried out. [Results] The friction power consumptions and orbital paths calculated by the dynamic model are consistent with the measured results, which verifies the correctness of the model. [Conclusions] The four supporting bearings of the test machine are in the state of the hydrodynamic lubrication, while the tested bearing is in the mixed lubrication at the Top Dead Center. With the increase of the bearing clearance, the minimum oil film thickness increases first and then decreases, and the best lubrication state can be obtained when the tested bearing clearance is about 20 μm. Compared with the bearing model based on rub impact and EHD model, the EHD model can obtain higher accuracy of the bearing loads.Hopefully, this paper could provide theoretical guidance for the lubrication performance design and high-precision modeling of journal bearings.