The catalysts, 5 wt% Na2WO4 -2 wt% Mn on mullites sintered at 1200°C, 1300°C, 1400°C, and 1500 °C, were prepared by incipient wetness impregnation method for the oxidative coupling of methane (OCM) reaction in a fixed-bed quartz tube reactor. These catalysts were characterized by XRD, XPS and BET method. The XRD pattern of Na2WO4-Mn/mullite indicated that the main crystal phase of metal oxide was MnWO4. From the XPS spectra, the results revealed the information on Na, W and Mn species distributed on the catalyst surface. For catalytic activity testing, Na2WO4-Mn/mullite sintered at 1300 °C showed the highest C2 selectivity of 11.4% and Na2WO4-Mn/mullite sintered at 1400 °C showed the highest CH4 conversion of 56.6%.