The present invention aims at converting factor IX into a molecule with enhanced activity which provides an alternative for replacement therapy and gene therapy for hemophilia B. Using recombinant techniques, factor IX having substitution of amino acid residue of SEQ ID NO: 7 at amino acid position selected from the group consisting of 86, 277, and 338 (exclude the circumstance of a single substitution at amino acid position 338) exhibits better clotting activity than recombinant wild type factor IX.