In the present work, narrow band gap AgBr nano-particle decorated TiO2 nanotubes arrays (AgBr/TiO2 NTAs) photoelectrode was successfully fabricated through anodization, followed by ultrasonic assisted precipitation process. Subsequently, morphologies and chemical structures were investigated through scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). In addition, the optical and photoelectrochemical (PECH) properties were recorded through Ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), transient photocurrent density and Mott-Schottky measurements. Furthermore, the photocatalytic (PC) efficiency was evaluated through the yield of hydroxyl ((OH)-O-center dot) radicals and degradation of 4-CP under visible light illumination. All results indicated that as-fabricated AgBr/TiO2 NTAs photoelectrode displayed superior PC performance, which was mainly ascribed to the intense visible light absorbance and high charge separation efficiency. Moreover, the intermediates and toxification change during PC degradation of 4-CP were elucidated according to the UPLC-MS/MS measurement and luminescent bacterial tests.