Abstract: Differential pulse stripping voltammetric behavior of vitamin K3 at the glassy carbon electrode (GCE) was studied in this paper.In a medium of ammoniacal buffer (pH 9.0),a pair of anodic-cathodic peak of vitamin K3 appeared in the cyclic voltammetric scanning.Mechanism of the electrode reaction was discussed.A linear relationship between the cathodic stripping peak current and VK3 concentration in range of 2.0×10-6-1.0×10-4mol·L-1 was held (r=0.998 5),with a detection limit of 4.0×10-7mol·L-1.RSD was 115% for the determination of VK3 at level of 1.0×10-5mol·L-1 (n=7).Recovery of the method was 97.3%-102.5%.The method has been applied to the determination of VK3 in medical injection.