Disclosed are an anti-bFGF humanized double-stranded antibody with stable disulfide bond, the preparation method and the applications thereof. The amino acid sequence of the anti-bFGF humanized ds-Diabody is shown in SEQ ID NO.1. The nucleotide sequence of gene encoding the anti-bFGF humanized ds-Diabody is shown in SEQ ID NO.2. By site-directed mutation, two cysteine residues are introduced into VL and VH domain of anti-bFGF Diabody, thus introducing the disulfide bond and form ds-Diabody. It is shown by experiments that the obtained ds-Diabody has the following advantages: enhanced stability; better affinity when binding to the specific antigen bFGF; moderate relative molecular weight, good tumor targeting, more powerful in tumor tissue penetration, and higher blood clearance rate, showing a broad application prospects in the clinic diagnosis and tumor therapy.