This study investigates the potential of dual-fuel combustion for reducing emissions with same power. Dual-fuel combustion controls the combustion by two fuels with different auto-ignition characteristics and this study uses DME and diesel that show different characteristics of evaporation and auto-ignition. In the previous work, we focus on the characteristic of combustion and emissions under single cylinder engine and ignition is done by compression ignition. Pre-mixture is formed by injecting low-pressure DME into an intake manifold and high-pressure fuel (diesel or DME) is injected directly into the cylinder. Both direct diesel injection and port fuel injection reduced the significant amount of Soot, CO and NOx in the homogeneous charge compression ignition engine due to present of oxygen in DME. In addition, when injecting DME directly in cylinder with port DME injection there is no changes in emissions and energy consumption rate even operated by homogeneous charge compression ignition.