The present invention relates to a method for producing the activated catalyst for Fischer-Tropsch synthesis comprising: a first step of reducing a catalyst for Fischer-Tropsch synthesis; a second step of preparing liquid hydrocarbon in which a part or all of molecular oxygen is eliminated; and a third step of introducing the reduced catalyst prepared in the first step into the liquid hydrocarbon prepared in the second step while blocking its contact with air. Since the reduced catalyst used for Fischer-Tropsch synthesis is introduced into liquid hydrocarbon from which molecular oxygen is removed or coated by liquid hydrocarbon, the catalyst for Fischer-Tropsch synthesis activated based on the present invention maintains a high activity even if exposed to the air for a long time, thereby easily facilitating the long-term storage and long-distance transfer of the reduced catalyst.