Abstract: A kind of conductive composite powder of TiO₂ coated with Sb-doped SnO₂(ATO) were prepared by wet chemical method.The morphology,resistivity,conductive mechanism of the ATO/TiO₂ conductive composite powder was studied.ATO was absorbed to the surface of TiO₂ particles by Van Der Waals force and electrostatic force,The complete network of conductive basic framework was determined by ATO content in TiO₂ particles surface.Before reaching a percolation threshold(V_C < 0.0689),the conductive ATO content was relatively smaller,the large-scale conductive network has not yet formed,so the resistivity of ATO/ TiO₂ powder changed slow with ATO content.When V_C=0.0689-0.1562,the probability of the chain network of conductive channel was greater,the connection between the ATO has undergone a qualitative change,and a three-dimensional conductive network structure was gradually formed,the resistivity of ATO/TiO₂ conductive composite powder changed dramatically with ATO content,and when V_C>0.1562,the conductive network connection became full,again the change of the resistivity of ATO/TiO₂ composite powder becamed slow with ATO content.