The response characteristics of the new biosensor developed by the co-immobilization of root tissue of sunflower and ferrocene in a carbon paste matrix for the amperometric determination of hydrogen peroxide were evaluated. In the range of electrode potential examined(-0.35 ~ -0.10V vs. Ag/AgCl), it responded in the wide range of pH and its biocatalytic stability was superior. Also, it`s detection limit was 2.5×10-6M (S/N=3) and it had relatively good selectivity to the materials considered to disturb the response. The result of this biosensor study using root tissue of sunflower can be utilized as the basic information for the determination of hydrogen peroxide.