<p>This paper provides an in-depth analysis of the effects of exhaust gas recirculation (EGR) coupled with injection parameters and cetane number (CN) on the performance of diesel engines. Test results can be obtained that the CN increased, the coupled EGR rate increased, the peak of cylinder pressure (CP) and the heat release rate (HRR) decreased significantly, the combustion duration (CD) shortened by 6.4%, exhibiting a pronounced downward trend. The coupled injection pressure increased, CO and HC emissions increased by 31.6% and 2.7%, the number concentration of Particulate matter(PM) decreased, and the total mass concentration of PM decreased by 50.82%, and the NOx emissions decreased by 45.16%. The increase of CN coupled with the increase of EGR rate, the peak of HRR decreased significantly by 25.3%, Ignition delay time(ID) and CD showed an opposite trend, the coupled injection timing was delayed, CO and HC emissions increased by 72.7% and 66.1%, respectively, while NOx emissions decreased by 76.5%, peak of PM concentration increased, and the total mass concentration of PM increased by 48.65%. As the EGR rate increased, the PM concentration of the fuels increased and then decreased. With the increase of EGR rate, the PM concentration of the fuel showed a trend of first increasing and then decreasing, and the peak corresponded to the particle size shifted to the direction of large particle size. The particle size peak of the PM reached 70–80&#xa0;nm. The CN = 53.9 fuel has no pre-injection heat release under different EGR conditions, significantly affecting the CP and HRR.</p>