Abstract: The effects of different frictional losses parameters on the performance of a Miller cycle during the finite time thermodynamic are investigated. In the cycle model, parameters frictional losses computed from the empirical correlation, the specific heat ratio are varied with temperature, the internal irreversibility described by using the heat transfer loss are considered. The relations between brake power and frictional losses parameters and between thermal efficiency and frictional losses parameters are derived. Moreover, the effects of frictional losses parameters on the cycle performance are analyzed. The results show that the engine RPM and inlet valve diameter are more effective on performance of a Miller engine. Also, the point of maximum brake power of Miller cycle is at compression ratio of 8. The results are of importance to provide good guidance for the performance evaluation, improvement and design of practical a Miller engines.