SnO2-TiO2 composite thin films were fabricated on soda-lime glass with sol-gel technology. By measuring the contact angle of the film surface and the degradation of methyl orange, we studied the influence of SnO2 doping concentration, heat-treatment temperature and film thickness on the super-hydrophilicity and photocatalytic activity of the composite films. The results indicate that the doping of SnO2 into TiO2 can improve their hydrophilicity and photocatalytic activity, and the composite film with 1-5 mol% SnO2 and heat-treated at 450degreesC is of super-hydrophilicity. The optimal SnO2 Concentration for the photocatalytic activity is 10 mol% and larger film thickness is helpful to reduce the contact angle of the composite films. (C) 2002 Elsevier Science Ltd. All rights reserved.