The invention provides an optical fiber insulator. Since glass filament winding tube is curved and formed in one time by jointly winding naked filaments immersed with epoxy and glass filaments, the electrical performance and the mechanical performance of the insulator are satisfied, meanwhile, the interface problem is solved, the transmission stability of an optical signal and the safe reliability of a product are improved. Moreover, a winding tube placing groove and a clamping groove are arranged on an end connection element, and thus, the connection among all parts is more firm. A line outlet is further arranged on the end connection element, so that optical fiber is more convenient to extend.