For the first time in this work, we manage to synthesize single-crystalline NaNb0.875Ta0.125O3 wires by combining the advantages of one-dimensional (1D) nanostructure and heteroatom doping strategy. Careful Ta doping was performed to figure out the correlation between morphological and structural evolution as well as the photocatalytic performance towards H2 generation. It was found that, the as-prepared NaNb0.875Ta0.125O3 wires presented a highest and stable photocatalytic performance, which was appropriately 41 and 2 folds higher than that of bare NaTaO3 and NaNbO3. The optical activity was mainly ascribed to the synergistic effect between appropriate Ta doping and perfect 1D wire-like morphology, which resulted in fewer defects, improved charge transfer efficiency and higher reduction capability of electrons. On the other hand, a possible photocatalytic mechanism of photocatalytic H2 production was proposed in detail. This work creates a new perspective into designing multi-component materials and understanding the mechanism of H2 evolution, which offers new opportunities for solar-energy conversion.