Previous studies have shown that co-catalysts play a pivotal role for improving both the activity and reliability of semiconductors in photocatalytic hydrogen production, however, designing highly efficient and cost-effective co-catalysts to replace expensive and rare metals is still a big challenge. In this work, DFT (density functional theory) is utilized to guide the application of CoP NWs (nanowires) as an earth-abundant co-catalyst for photocatalytic hydrogen production. Metallic 1D CoP NWs is rationally integrated with Zn0.5Cd0.5S solid solution semiconductor for the first time, to induce a remarkably improved photocatalytic hydrogen production activity of 12,175.8 mu mol h(-1) g(-1), which is 22 times higher than that of the pristine Zn0.5Cd0.5S. This outstanding activity benefits from the collaborative advantages of excellent metallic conductivity and the rigid 1D nanostructure of CoP NWs. Moreover, the mechanism investigations demonstrate that this excellent activity arises from the strong electronic coupling, favourable band structure, highly efficient charge separation and migration based on the powerful characterizations, such as time-resolved PL decay spectra and photoelectrochemical methodology. This work brings new opportunities to employ 1D co-catalysts on photocatalysts for improving the catalytic activities in hydrogen production from water.