A ball head connecting device of electric transmission line insulators comprises a strip-shaped hook body which is composed of an upper straight section and a lower arc-shaped hook section. A hanging hole is formed in the upper straight section, and a T-shaped groove hole into which an insulator ball head can be embedded is formed in the lower arc-shaped hook section. The strip-shaped hook body is made of hard metal materials which can meet the strength requirement for bearing the whole weight of a string of insulators. An arc-shaped hook of the lower arc-shaped hook section 2 can be effectively matched with the ball head surface of each insulator. The upper straight section of the strip-shaped hook body is manufactured into an oval shape or a circular periphery shape, and the hanging hole in the upper straight section is correspondingly manufactured into an oval hole or a circular hole. The lower arc-shaped hook section, corresponding to the T-shaped groove hole, is also manufactured into a T-shaped periphery shape. The ball head connecting device of the electric transmission line insulators has the advantages that carrying and maintenance operations on the insulators can be effectively, safely and fast assisted.