In this report, a series of self-organized TiO₂ nanotube arrays were prepared by anodization of titanium foil in mixed electrolytes composed of water, ethylene glycol, and NH₄F. Their photoelectrochemical (PEC) performance as a photoanode was characterized by the PEC water-splitting hydrogen (H₂) generation reaction. The internal relationship between the TiO₂ nanotube arrays (TNTAs) morphology and their PEC performance was thoroughly investigated. Our results show that when the etching time is 10 hours, the length of the as-prepared TNTAs is about 20.78 μm and the measured photocurrent density is around 1.25 mA·cm^-2 with applied bias voltage 0.6 V (vs. Ag/AgCl) under simulated sunlight irradiation, which is 976 times higher than that of the TiO₂ substrate without nanotubes architecture (0.00128 mA×cm^-2). More interestingly, the results of the IPCE measurement show that the band-gap of the as-prepared TNTAs is reduced from 3.20 to 2.83 eV. The corresponding optical response limit is also extended from 400 nm to TiO₂ nanotube arrays is 510 nm, which indicates that the increasement of the TNTAs PEC performance benefits from the great improvement of its utilization of both the UV and visible light irradiation.