Bi2-xTixO3+x/2 (x = 0.05, 0.10 and 0.15) photocatalysts are prepared by solid-state technique. The band gap of the prepared sample was estimated from the onset of UV-Vis absorption spectra. The photocatalytic activities of as prepared samples are investigated under UV light irradiation for the decomposition of methyl orange (MO). It has been observed that the rate of decomposition of MO increased with increasing Ti4+ content in the present samples. Moreover, it shows better photocatalytic activity than undoped Bi2O3 and TiO2. The lowest band gap is observed for x = 0.15 sample, i.e. 2.55 eV, which also showed the highest photocatalytic activity in the present sample.