A feasible and fast method to fabricate hydrogen peroxide sensor was investigated by graphene-manganase nanocomposite carbone paste electrode. In the present work, in first step, the graphene was synthesized by chemical method and in second step, manganese oxide nanoparticle was doped on graphene. graphene-manganase nanocomposite was characterized by FTIR and SEM. The nanocomposite shows a high conductive and sensitivity for hydrogen peroxide determination as shown by electrochemical impedance spectroscopy. Graphene-manganase nanocomposite carbone paste electrode was used for sensing of hydrogen peroxide by choronoamperometry with a potential of 250 mV (Ag/AgCl), in 0.1 M phosphate buffer solution at pH= 7. The linear concentration rang of sensor is 8.8-263.3 μM, and with detection limit of 1.04 μM. Also, the life time of sensor is infinite.