Heat resistance insulating paint was prepared by epoxy organosilicon resin, ultrafine inorganic filler and organic assist. And the application of insulating paint to the magnetic wire and lead wire of coil assembly for nuclear control rod drive mechanism was performed. The main performance indexes of heat resistance, radiation resistance of the magnetic wire and lead wire was investigated, The experiment results show that the heat resistance insulating paint with additive of ultrafine inorganic filler has good heat resistance, flexibility and adhesion, which is suitable for nuclear control rod drive mechanism because the heat resistance and radiation resistance of the magnetic wire and lead wire are improved greatly.Cited