A new method is presented for the mixed lubricated piston skirt-liner subsystem in a four-stroke gasoline engine, with the consideration of the cylinder liner vibration. This method is established by coupling Multibody Dynamics, Thin-Film Flow and Solid Mechanics modules in real-time through COMSOL Multiphysics software. The Multibody dynamics module is used to characterize the relative motion between each component of the system. The Thin-Film Flow module, based on this relative motion, simulates the lubrication of the piston-liner friction pair, and is further coupled with the elastic deformation derived from the Solid Mechanics module to achieve the elastohydrodynamic lubrication (EHD) simulation. In turn, the lubrication performance of the piston-liner friction pair affects the vibration of the cylinder liner through the Solid Mechanics module, and also influences the piston secondary motion through the Multibody dynamics module. Some physical parameters of the four-stroke gasoline engine, are investigated to reveal their influence on the dynamics and tribological performances of engine. Then, the dependences of performances on the rotation speed of the engine is also studied.