This review covers recent research on counter electrodes using platinum (Pt), carbon and conducting polymers as catalysts for the reduction of triiodide in the dye-sensitized solar cell. Different types of counter electrode preparation methods and their advantages and disadvantages are compared. The inadequacy of the counter electrode with the precious metals and the advantages of the non-metallic-type counter electrode are pointed out. Especially, recent research on the Pt counter electrode in our group is discussed concerning with the reaction mechanism of the triiodide (I3-)/ iodide (I-) redox couple on the Pt counter electrode.