Abstract: In room temperature, the anodic polarization curves of Pt and Pt-Ti electrodes are determined in different concentration of HNO_3 and hydrazine. The electrolysis oxidation and catalysis decomposition of hydrazine in HNO_3 are studied. The results show that Pt-Ti electrode is better than Pt for the oxidation of hydrazine. The velocity of hydrazine electrolysis reaction increases with the increase of current density and is less affected by concentration of HNO3. The velocity of hydrazine catalysis reaction increases with increasing the temperature and acidity. Both electrolysis oxidation and catalysis decomposition can reduce the concentration of hydrazine to 10-5 mol/L.