The fracture problems of the composite insulators are the key problems to threat the security and stability of the transmission line.In order to analyze the types and causes of the fracture problem,this paper studies the fracture samples of the composite insulators and classifies the fracture types of insulator hardware and FRP rod.Studied shows that the causes included the invalidation of sealant,breakage of the sheath and splice failure between the FRP rod and the sheath.To solve the problems,three solutions including performance test,on line detection and technical transformation of the composite insulators in the important passage are proposed.And preventing suggestions to the fracture problems are provided.