Provided is a method for preparing a catalyst for a dehydrogenation reaction of formate and a hydrogenation reaction of bicarbonate, the method including: adding a silica colloid to a polymerization step of polymerizing aniline and reacting the resulting mixture to form a poly(silica-aniline) composite; carbonizing the corresponding poly(silica-aniline) composite under an atmosphere of an inert gas; removing silica particles from the corresponding poly(silica-aniline) composite to form a polyaniline-based porous carbon support; and fixing palladium particles on the corresponding polyaniline-based porous carbon support to prepare the catalyst.