Abstract: In order to explore the impact laws of split injection strategies on combustion noise and emission characteristics, experimental studies and CFD simulations were conducted on a heavy duty diesel engine with common rail sytem, by varying different pilot and post injection parameters. The results showed that the combustion noise was mitigated by introducing fuel pilotinjection; the NOx emission could be reduced by pilotinjection combination of 1.0 mg fuel quantity and/or 45°CA injection interval, without penalty of PM emission too much. Besides, PM emission could be decreased under all postinjection conditions with no NOx increased. More important, through CFD simulation with HARR soot model revised showed that the turbulent flow motion caused by postinjection spray was one of the key factors enhancing soot oxidization.