Undoped and Al-doped SnO2 thin films have been prepared by sol–gel spin coating process on glass substrate  for different doping (0, 2.5 ,5 ,7.5,10)% The starting precursor was used as tin chloride dihydrate (SnCl2.2H2O), ethanol , with and without stabilizer. As annealing in a temperature 500°C for one hours, the results of (X-Ray ) diffraction showed that the films have a Polycrystalline structure and increased intensity when use  stabilizer and orientation was (020) with lattice constants (a=4.796, b=5.796, c= 5.193) Å.   The surface morphology of the (SnO2: Al) thin films have been studied using atomic force microscopy (AFM) which indicated that the grown films showed good crystalline and homogeneous surface. The Root Mean Square (RMS) values and surface roughness of the films increased with increasing doped concentration specify when use  stabilizer.