Measurements of exhaust particle mass, number concentration, and number size distribution and NOx, HC, and soot concentration from an engine fueled with oxygenated GTL (dimethoxy methane (DMM) blended with GTL (gas-to-liquids)) were carried out by using a single-stage dilution system. The results indicate that, compared with the baseline GTL, the oxygenated GTL were found to decrease the mass concentration of total particles (10-487 nm) as well as the number concentration of the accumulation mode at all loads, and the reduction level was correlated with the oxygen content and load. Meanwhile, the exhaust particle number concentration of the nucleation mode increased with oxygen content of oxygenated GTL. Compared with baseline GTL, under the same engine conditions, the total particles number concentration for oxygenated GTL increased significantly at middle-low loads (<= 50% load) but deceased at loads of <= 75%. Also, the geometrical mean diameters of exhaust particles decreased by 3-10 nm. Furthermore, with the addition of DMM, the NOx emissions increased slightly at middle-low loads, but decreased at high loads (loads :75% of the full loads); the HC emissions increased slightly; the smoke emissions decreased significantly; and the reduction of smoke increased with the oxygen content of oxygenated GTL.