The present invention discloses a novel polypeptide capable of binding Taq DNA polymerase, a polynucleotide encoding the polypeptide, a recombinant vector comprising the polynucleotide, a cell having the recombinant vector introduced therein, a method of producing the polypeptide using the recombinant cell, and a hot-start PCR composition comprising the polypeptide. The polypeptide of the present invention is capable of binding specifically to Taq DNA polymerase to inhibit the activity of the polymerase, and thus may be effectively used in hot-start PCR using Taq DNA polymerase.