Complete composition-tuned ZnxIn1−xS (0<x<1) quantum dots were deposited on TiO2 nanotube arrays by the successive ionic layer absorption and reaction (SILAR) method. The deposition of ZnxIn1−xS nanoparticles on the upper and inner surface of the TiO2 NTs was confirmed by field emission scanning electron (FE-SEM) and transmission electron microscopes (TEM). The ZnxIn1−xS/TiO2 nanotube arrays exhibited high absorption in the visible light region due to the narrow band gap of ZnxIn1−xS. Zn0.4In0.6S/TiO2 NTs electrodes showed the optimal photoelectrochemical properties under visible light illumination.