The highly ordered TiO2 nanotube arrays (2-step TiO2 NTs) were prepared via a facile two-step anodization method. The micro morphology, crystal form, elemental composition and photoresponse were characterized by SEM, XRD and UV-vis DRS respectively. The images of SEM showed that the 2-step TiO2 NTs exhibited superior array effect. At the same time, the UV-vis DRS showed that the range of photoresponse shifted towards long wave obviously. Nitrobenzene was utilized to be a target organic pollutant to characterize the catalyst performance. The result showed that nitrobenzene could be degraded by the 2-step TiO2 NTs effectively, and the photocatalytic activity of 2-step TiO2 NTs was far better than the 1-step TiO2 NTs. The photocatalytic degradation efficiency of nitrobenzene was improved remarkably. The reason of the efficiency improvement was caused by the highly ordered structure of the 2-step TiO2 NTs which increased the specific surface area of the photocatalyst. Therefore, the optical channel was increased, photoabsorption region was broadened and the photo-quantum efficiency was improved.