Taking an inline 3cylinder gasoline engine as the research object， the model was built and verified its correctness. With this model, the influence of piston ring structure on the lubrication of piston ring and cylinder liner pair was analyzed. The results show that the friction loss of piston ring and cylinder liner friction pairs will increase when the radial barrel surface height of piston ring is too large or too small. The smaller tangential elastic force is preferred as long as the engine runs steadily. The opening gap has a great impact on the gas leakage of cylinder and the opening gap between 0.38 mm and 0.40 mm is found optimal when the engine is in cold state.
