Conductive fiber was prepared by coating antimony-doped tin oxide (ATO) on silicon dioxide glass fiber using a heterogeneous nucleation method. The varying trend of resistivity with the calcination temperature of the ATO-coated silicon dioxide fiber was almost the same as that of the pure ATO. The resistivities of the ATO-coated silicon dioxide fibers with the coating amounts of 100%, 75%, 50%, 25%, and 12.5% and treated at 500-1200 oC were all below 200 Ω·cm. As the conductive additive, the ATO-coated silicon dioxide fiber can maximally save the ATO amount because of the bridge effect resulting from its high aspect ratio, which makes it possible to form a more completed conductive net in the ceramics for a small quantity of conductive fibers. For instance, about 77.8% of ATO amount can be saved when the ATO-coated silicon dioxide fibers with 12.5% coating material are used as conductive filler.