The present invention relates to the preparation of a dimerized TMP-TMP-HSA fusion protein and its application. Said fusion protein is comprised of one HSA and tandem TMP-TMP, which are linked to a dimerization domain by a peptide liker, and the dimerization domain can ensure said fusion protein to be correctly dimerized during its expression. Said tandem TMP-TMP can be linked to an amino terminal or a carboxyl terminal of HSA.