A comparative study was made on photocalytic activity of ZnO, SnO2 and their composite. A simple mechanochemical method was used for preparation of composite. The photocatalytic efficiency of ZnO-SnO2 composite was compared with pure ZnO and SnO2. The effect of various parameters such as pH, dye concentration, semiconductor amount and light intensity was observed. The optimum conditions for this degradation were obtained as: Rose Bengal=6.0 × 10-6 M, pH=7.5, amount of composite=0.08 g and light intensity=60.0 mWcm-2. It was found that coupled chalcogenide ZnO-SnO2 show better photocatalytic activity as compared with ZnO and SnO2 alone for the degradation of rose Bengal in the presence of visible light.