The invention relates to a pre-twisted type composite stay insulator and belongs to the field of electricity protection. The pre-twisted type stay insulator comprises a pole stay, and is characterized in that the pole stay is in a sectional structure; the sectional pole stays are connected by insulators; the insulators are composite material insulators and a group of pre-twisted wires are wound on the insulators; and each pre-twisted wire is a tension resistant pre-twisted wire, and both ends of the pre-twisted wire are connected with the pole stay respectively. The stay insulator is simple in structure, low in manufacture cost and light in material and has the performance higher than that of the traditional ceramic insulator; in addition, the stay insulator is convenient to install and easy and convenient to operate, can be mounted by one normal repairer without being subjected to professional training, and thus the assembling working efficiency is greatly improved; and the device is small in volume, light in weight and high in strength, and the reliability of the stay insulator can be improved after the stay insulator is installed on the pole stay.