Environmental regulations are being reinforced for the solution of environmental pollution, that are global issues. Exhaust gas regulations of off-road engines also demand stepwise reduction emission from beginning of Tier 4 interim(2013). Characteristically, Tier 4 regulation apply the NRTC mode which is a transient cycle. And technical studies using NRTC mode are uncommon. In this study, for satisfy the Tier 4 final regulation on the NRTC mode, experimental study was conducted using a 3.4 L off-road engine. Fuel injection timing and injector hole number are chosen as parameters for investigation of combustion and exhaust gas characteristics on off-road diesel engine.