Abstract: In view of the problem that a 10 kV overhead insulated conductor is frequently cracked after short-term operation, the fracture mechanism and causes of insulated conductor are analyzed by means of appearance analysis, mechanical properties test, microstructure observation and fracture micro area analysis. The results show that the contact wear between aluminum strand and strain clamp is the main reason for the fracture of overhead insulated conductor. To prevent such fracture from recurring, this paper puts forward suggestions of using wrapping soft aluminum tape and installing anti-vibration whip or anti-vibration hammer at appropriate parts.