This study synthesized the In(OH)3–In2S3 nanosheet via a simple hydrothermal method. The different amounts of In(OH)3–In2S3 nanosheet used to synthesize In(OH)3–In2S3–Cu2O composite by a wet chemical method. FESEM, FETEM, XRD, XPS, BET, UV–vis DRS, and PL spectroscopy characterized the In(OH)3–In2S3–Cu2O composite. Compared with In(OH)3–In2S3 nanosheet, In(OH)3–In2S3–Cu2O composite can exhibit the synergistic effects of higher specific surface area, higher light-harvesting capacity, and accelerating the separation and migration of photogenerated charge carriers. In addition, In(OH)3–In2S3–Cu2O nanofiber was fabricated via a facile electrospinning process at the different amounts of In(OH)3–In2S3 nanosheet. The manufacturing process offers many advantages, such as simplicity, low temperature, and without templates. The effect of operational parameters (such as the reaction conditions of photocatalysts, pH values, sacrificial reagents, and light sources) on the photocatalytic hydrogen production of In(OH)3–In2S3–Cu2O nanofiber was investigated. The results indicate that the appropriate reaction conditions of In(OH)3–In2S3–Cu2O nanofiber can reveal higher efficient photocatalytic water splitting than commercial TiO2 or ZnO nanofiber under blue light LED excitation. Furthermore, In(OH)3–In2S3–Cu2O nanofiber can provide a simple fabrication process, high photocatalytic activity, and high reusability shall be beneficial for the practical application of photocatalytic hydrogen production.