Controllable and efficient photo-catalyst is of particular importance not only for improving photo-catalytic activity of hydrogen evolution, but also for achieving more excellent performance of semiconductors in practical applications. Here two n-type semiconductors (cobalt phosphide (CoP) and MIL-125-NH2) as well as their complex catalysts (CoP/MIL-125NH(2)) are reported and the unique role of cobalt phosphide in CoP/MIL-125-NH2 is systematically investigated for boosting hydrogen evolution activity based on MIL-125-NH2 under visible light-driven. CoP/MIL-125-NH2 can exhibit a 267-fold enhanced catalytic activity compared to the pristine MIL-125-NH2. Moreover, the excellent catalytic property of the as -prepared catalysts has been investigated in detail by several means of characterization. The findings are that the distinctive morphology and relatively ideal S-BET of MIL125-NH2 play particular role in the highly efficient photo-catalytic reaction system, and the highly efficient catalytic property of CoP/MIL-125-NH2 mainly depends on unique role of cobalt phosphide having excellent photo-catalytic performance for hydrogen evolution. Based on the above results, the possible mechanism of photo-catalytic hydrogen evolution is speculated. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.