In light of the lack of quantitative calculation in cylinder to cylinder variation and cycle to cycle variation research, the original flywheel data are processed to calculate the max acceleration of cylinder to cylinder variation, cycle to cycle variation and the LNV of internal combustion engine flywheel using MATALAB software. The correlation between the above three parameters and corresponding cylinder pressure parameters is analyzed. The varying pattern of the three parameters with engine speed and loads is obtained. The analysis results show a very high positive linear correlation of the max acceleration of cylinder to cylinder variation, cycle to cycle variation and LNV with the corresponding cylinder pressure parameters. As the engine idle speed increases, the cylinder to cylinder variation decreases and the cycle to cycle variation changes little. As the engine idle speed increases, the LNV initially decreases, then changes little when the engine idle speed passes a certain value. All three parameters decrease with increasing engine loads, but the engine loads have a larger effect on cycle to cycle variation than on cylinder to cylinder variation.