To evaluate the emission characteristics of engineering vehicle diesel engine effectively and find a suitable emission control strategy, the emission characteristics experiment of China CYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN ICYRILLIC CAPITAL LETTER BYELORUSSIAN-UKRAINIAN I engineering vehicle diesel engine was conducted with and without DOC+ DPF. The experiment took high-idling, low-idling, and free-acceleration as testing conditions, and used NanoMet3 particulate analysis system to measure PM mass concentration, number concentration and mean particle size. The gaseous emissions (NOx, NO2, CO, HC) were analyzed by flue gas analyzer Testo350. The results showed that the PM emission characteristics of engineering vehicle diesel engine improved observably under three different conditions With DOC+ DPF. PM mass emissions reduced by over 85%, and PM number emissions were more than reduce of 90%. The metabolic characteristics of PM mean particle size were sample A < sample B < sample C and high-idling < low-idling < free-acceleration. NOx concentration was not influenced obviously by DOC+ DPF, but NO2/NOx value increased. Besides, DOC+ DPF made CO emissions decreased by 85% and HC emissions decrement between 50%similar to 80% under different conditions. DOC + DPF could improve the emission characteristics of engineering vehicle diesel engine efficiently, which was easily affected by diesel quality and equipment working hours.