The utility model discloses an anti-drop type ball joint structure used for overhead power transmission lines. The anti-drop type bulb joint structure comprises a ball head rod with a ball head at one end and a bowl-like head rod with a bowl-like head at one end, wherein the bowl-like head is internally provided with a bowel-like cavity provided with an open end and capable of accommodating the ball head, the bowl-like head is provided with a locking pin capable of clamping the ball head in the bowl-like head and preventing the ball head from moving up and down, and an annular clamping pin capable of clamping the ball head in the bowl-like cavity and preventing the ball head from moving front and back is clamped on the ball head rod. According to the anti-drop type ball joint structure, the annular clamping pin clamped on the ball head rod is mainly used for assisting the stress on the locking pin and preventing the ball head from moving front and back, so that the situation that the locking function of the locking pin of the bowl-like head is lost due to the long-term extrusion is prevented, and the stability of the connection between the ball head and the bowl-like head is enhanced. The anti-drop type ball joint structure has the advantages of simple structure and favorable stability and is suitable for overhead power transmission lines.