Abstract: A fracture occurred in the OPGW clamp of a certain ultra-high voltage transmission line. The cause of the clamp fracture was analyzed using macroscopic observation, chemical composition analysis, metallographic examination, mechanical property testing, scanning electron microscopy analysis. The results show that the microstructure of YL112 aluminum alloy was mainly composed of α-Al and needle like eutectic silicon, and a second phase of Al-CuAl₂-Si precipitated between α-Al and eutectic silicon. The second phase would reduce the corrosion resistance of aluminum alloy, resulting in a decrease in the tensile strength of the wire clamp during long-term operation.When the wire clamp was subjected to OPGW icing load, the needle like eutectic silicon near the shaft pin would intensify stress concentration, leading to the formation of crack sources in that area. At the same time, the needle like structure of eutectic silicon and the aluminum alloy casting holes provided conditions for crack propagation, ultimately causing the wire clamp to fracture.