In the present study, multilayer MoSe2/Mo nanostructures fabricated by surface selenization of Mo-coated glass substrates using magnetron sputtering, was proposed as a counter electrode (CE) catalyst in dye-sensitized solar cells (DSSCs) to speed up the reduction of triiodide I3- to iodide I-. The extensive cyclic voltammograms (CV) and Tafel curve analysis indicated that the current density of the optimized MoSe2/Mo CE was higher than Pt CEs due to the fast reduction species. Furthermore, the peak current densities of the MoSe2/Mo CE showed little degradation after consecutive 100 CV cycles, suggesting high electrochemical stability of the MoSe2/Mo CE. In addition, MoSe2/Mo CE exhibited lower charge-transfer resistance than Pt CEs. Finally, the DSSC assembled with the MoSe2/Mo CE showed a high power conversion efficiency of 9.57% under illumination of 100 mW · cm-2 (DSSC with Pt CE: 9.15%).