Antimony doped tin oxide (ATO) thin films were deposited onto silica coated soda lime silicate substrate by the sol-gel method using Sb(OC4H9)4 and Sn(OC4H9)4 as the precursor materials. Conductive tin oxide nano particles of different particle size were added into the sols. The films were subjected to heat treatment at t=500) for about one hour. Film structure and surface morphology has been investigated by means of atomic force microscopy (AFM). Room temperature electrical resistivity of the films was measured using the conventional four probe van der paul method. The influence of incorporation of conductive nano particles on the electrical conductivity of Sb-doped tin oxide films was studied. The correlation between the microstructure and the film electrical property has been obtained. The status of the nano particles in the films has also investigated by FTIR spectroscopy.