A SiO2 aqueous sol was prepared and mixed with the anatase TiO2 sol synthesized at low temperature in different molar ratios for the coating of cotton fabrics using padding-drying process. And then the photocatalytic activity of the resulting SiO2/TiO2-loaded cotton fabrics was evaluated in the degradation of Rhodamine B in water. The effect of the SiO2 content on the photocatalytic performance of the loaded fabrics was investigated with respect to dye decoloration percentage. UV-Vis spectrum was also used to examine the dye degradation process in the presence of the SiO2/TiO2-loaded cotton fabric. The results indicate that when the ratio of Si/Ti reaches 1:1-3, the finished fabrics have the best photocatalytic activity. Moreover, UV-Vis spectrum indicates that the addition of SiO2 on the cotton fabric can enhance the decomposition of the dye molecular azo linkages and aromatic rings.