The invention relates to a zinc ring for a V-shaped string DC porcelain insulator and an application thereof. The zinc ring is a ring which has a half thick circumference and a half thin circumference, and a smooth transition part is arranged at an interface between the half thick circumference and the half thin circumference. The cross section of the half thick circumference of the zinc ring is foreign-shaped. The shape of the cross section of the half thin circumference of the zinc ring is same with that of the cross section of the half thick circumference of the zinc ring, and furthermore the widths and the thicknesses of the two members are different from each other. According to the application, the zinc ring is coated on the surface of an iron cap in a slit between a V-shaped string DC porcelain insulator iron cap and a porcelain member; furthermore the half thick circumference of the zinc ring and an opening of a ball socket are arranged at a same side; a first linear part and a second linear part of the cross section of the zinc ring are respectively connected with the inner half part and the outer half part at the lower end of the iron cap in an abutting manner; and a bending part of a V-shaped broken line part is a dripping eave of the V-shaped string DC porcelain insulator. According to the zinc ring, the thickness at the dripping eave is maximal, thereby maximally improving protection function of the zinc ring and effectively preventing Fe-based electrical corrosion, and furthermore self mechanical performance of the insulator does not reduce. Furthermore the zinc ring has advantages of: small number of material consumption, and low cost.