Experimental studies were carried out to improve the ignition ability and combustion characteristics of ethanol-diesel blended fuel (EDBF) in order to limit the exhaust emissions of an ethanol-diesel fueled engine. 2-Ethylhexyl nitrate (2-EHN) and ditert-butyl peroxide (DTBP) were selected as the cetane improvers (CI) in the present study, which are applied to the blended fuel used for an inline four-cylinder supercharger-intercooler diesel engine. Experimental results show that the ignition ability of the blended fuel can be improved by adding CI into the blends, and, accordingly, the CO emission can be reduced slightly under the heavy load condition. Meanwhile, the HC emission can be improved when 2-EHN is applied but turns worse after DTBP is added to the fuel. In addition, the NOx emission can also be improved using both of these cetane improvers when the engine operates under low as well as moderate load conditions.