This paper investigated the influence of injector nozzle hole number on fuel consumption and exhaust emission characteristics of diesel engine. The engine used for the experiment was the 0.4L single-cylinder compression ignition engine which is modified from an 1.6L four-cylinder automotive diesel engine. The fuel injection equipment were operated under 250MPa injection pressure. Three injectors with identical hydraulic flow rate with various combinations of the nozzle hole number(8, 9, and 10) and diameter(105 μm, 100 μm, 95 μm) were compared. The indicated specific fuel consumption and NOx emission of three injectors were on same level because of the identical fuel flow rates and similar in-cylinder pressure traces. Without EGR, the particulate matter(PM) emission were lower with larger nozzle hole number. However, the NOx-PM trade-off were similar at low oxygen concentration with high EGR rate. Also, the effect of the nozzle hole number under same nozzle diameter were identified with 8- and 10-hole injectors with nozzle diameter of 95 μm. The 10-hole injector showed lower fuel consumption and PM emissions than 8-hole injector. These results showed that the higher fuel injection rate and wider fuel spray distribution by increasing nozzle hole number and maintaining nozzle diameter results the lower fuel consumption and PM emission. This research could provide a standard on the optimal design of hole number and diameter in automotive engine injector nozzles.