A grapgene modified glassy carbon electrode was fabricated by cyclic voltammetry and was characterized by IR,XRD and SEM techniques.The electrochemistry behavior of hydrazine on the modified electrode was also investigated.The results showed that the modified electrode had high electrocatalytic activity to the oxidation of hydrazine.Based on this,an amperometry technique for the determation of hydrazine was established.Under the optimum conditions,the oxidation peak current had linear relationships with concentration of hydrazine in the ranges of 1.0×10-8-4.4×10-7mol?L-1 and 4.4×10-7-1.3×10-4 mol?L-1 with a detection limit(3sb) of 9.9×10-9 mol?L-1.The proposed method was applied in the determination of hydrazine in simulation water with spiked recoveries of 100%.