Series of N-doped TiO2 nanotube array (NTA) films with various N-doping levels and tube lengths prepared by a facile one-step anodization method, simply changing NH4F quantity in electrolyte. crystal structures, morphologies and compositions of the samples were analyzed by XRD, SEM, TEM X-ray photoelectron spectra (XPS). The optical properties were investigated by means of absorption spectra and photoluminescence (PL) spectra. Their photocatalytic activities were assessed photodegradation of rhodamine B (RhB) solution and photocatalytic water splitting to hydrogen, respectively. The photocatalytic reaction mechanism was investigated and discussed. results show that NH4F quantity greatly influences the N-doping level and tube length of the TiO2 which subsequently affects the optical properties and photocatalytic activities. The and photocatalytic H-2 production activities of the N-doped TiO2 NTAs can be simply regulated by NH4F quantity in electrolyte during preparation. (C) 2016 Elsevier Ltd. All rights reserved.