Oriented TiO_2 nanosheet arrays with tunable doping concentration of oxygen vacancies were successfully fabricated via sodium borohydride liquid-phase reduction method,and were investigated as the photocatalyst for the degradation of methyl orange(MO). The results show that the photocatalytic activity of the oxygen-deficient nanosheet arrays could be significantly improved,and the optimal photo degradation rate for MO degradation was achieved to be 0.6 h~(-1),about 1.5 times higher than that of the unreduce...