Ammonia synthesis based on electrocatalytic nitrogen reduction reaction (NRR) by using renewable sources of energy under ambient conditions has attracted wide research attentions. Herein, we report that the noble-metal-free CuCo2S4/multiwalled carbon nanotube nanocomposite, which is synthesized via a facile one-step hydrothermal and sulfuration approach, can work as the high active and durable catalyst for electrocatalytic NRR. This nanocomposite achieves a high NH3 yield of 137.5 mu g h(-1) mg(cat)(-1) and a high Faradaic efficiency of 8.7% at -0.5 V vs reversible hydrogen electrode (RHE) in 0.1 M Na2SO4 solution, which outperforms CuCo2S4 counterpart and most reported NRR catalysts. These results reveal that the MWCNT in nanocomposite not only suppresses the aggregation of CuCo2S4 nanoparticles and maximizes the exposure of active sites, but also contributes to the synergistic effect between CuCo2S4 nanoparticles and MWCNT, and facilitates the interfacial reaction kinetics. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.