Abstract： The effect of polyoxymethylene dimethyl ethers (PODE) on the combustion, emission performance and fuel economy of a turbocharged intercooled commonrail diesel engine was investigated, in the cases of pure diesel and diesel blended with 10%, 20%, 30% PODE respectively. The results showed that the added PODE affects the engine combustion characteristic significantly.  Except for the lowspeed and lightduty engine mode, the blend of PODE decreases the heat release rate of the preinjection fuel, improves the atomozation performance of the main injection fuel, increases the active ingredients in combustion chamber before the main fuel injection, increases the pressure rising rate and heat release rate as well as the incylinder mean temperature in the main fuel injection period, and shortens the combustion duration. Under test conditions, with the increasing of blended PODE ratio, the incylinder maxium temperature and the fuel combustion speed of the main injection fuel increases while the combustion duration decreases. The emission investigation showed that with the mixtured PODE, the NOx emission increases, the HC emission decreases slightly but the CO emission remains unchanged. The fuel economy is improved by adding PODE.