We demonstrate a facile modification of rutile TiO2 and its anti-bacterial activity under solar irradiation. The modification of rutile TiO2 was done by microwave-assisted hydrothermal process with hydrogen peroxide (H2O2) as a solvent. The structural properties were analyzed by using XRD and Raman studies. The modified rutile TiO2 shows no change either crystalline phase or crystalline size. The formation of Ti-OH was observed in Raman study. The TEM analysis shows modification on the surface of rutile TiO2. The photocatalytic disinfection of Escherichia coli (E. coli) under solar irradiation shows double-times better performance by modified rutile TiO2 compared to rutile TiO2. The enhancement of anti-bacterial activity was attributed surface modification and Ti-OH.