Atomization and combustion characteristics of DME diesel engines is considerably affected by nozzle fuel flow characteristics of diesel injectors. The FLUENT was employed to numerically estimate fuel flow characteristics of DME engine nozzle. The influence of different inlet pressure, inlet fillet condition on the pressure distribution and the average jet velocity were studied. The results indicate that the minimum pressure value of the transition zone is proportional to the natural logarithm of the inlet fillet; the inlet pressure is parabolic in relation to the minimum pressure in the transition zone, and transition zone’s low pressure value is decreasing and the decreasing trend became more and more faster with inlet pressure increasing; the main influence factor of average flow rate is difference of inlet and outlet pressure, and with the inlet fillet radius increasing, the average flow rate of outlet is firstly increasing and then decreasing.