In this research,undoped SnO2 films and palladium doped films (with various doping concentration 1, 3, 5%) were prepared in chemical spray deposition method in which the films were deposited on glass slides and on porous silicon.The surface topography of the films and the porous silicon was studied by using the Scanning Electron Microscopy (SEM) and the Atomic Force Microscopy (AFM). The study showed that the surface structure of the deposited films was nano structural and the value of the grain size was (9.22 nm). On the other hand, it was found that the surface roughness increased after doping from (17 to 24.5 nm), and the x-rays diffraction showed the appearance of level (110). It was also detected that the prepared doped and undoped SnO2 films were of polycrystalline structural of a tetragonal type.