The invention provides a DC porcelain insulator zinc ring and an application thereof. The zinc ring has a uniform cross section which is foreign-shaped. A cross section contour is composed of the components of: a first straight line part, a first camber line part which is formed through outward and upward extension from the outer end of the first straight line part, a second camber line part which is formed through downward and outward extension from the upper end of the first camber line part, a V-shaped broken line part which opposes the first straight line part and has a middle part that projects downwards, a second straight line part for connecting the inner end of the V-shaped broken line part and the inner end of the first straight line part, and a third straight line part for connecting the outer end of the V-shaped broken line part with the lower end of the second camber line part. According to the application, the surface of an iron cap is coated by the zinc ring in a gap between the DC porcelain insulator zinc ring and a porcelain member. The first straight line part and the first camber line part respectively abut against the inner half part and the outer half part of the lower end of the iron cap. The bending part of the V-shaped broken line part is a dripping eave of the DC porcelain insulator. The DC porcelain insulator zinc ring has high protection function and furthermore does not cause mechanical performance reduction of the insulator.