Reasonable design of efficient and stable catalysts with low cost and abundant natural reserves is vital for electrocatalytic water splitting. Herein, novel nanotremella-like Bi2S3/MoS2 composites with different mass ratios between Bi2S3 and MoS2 have been successfully prepared through a hydrothermal approach and further applied to hydrogen evolution reaction (HER) in 1.0 M KOH electrolyte for the first time. When the mass ratio of Bi2S3 and MoS2 is 5:5, as-prepared nanotremella-like Bi2S3/MoS2 (marked as BMS-5) manifests favorable HER catalytic activity with overpotential of 124 mV at current density of 10 mA cm(-2) and relatively low Tafel slope of 123 mV dec(-1). Moreover, it exhibits an extraordinary durability for uninterrupted hydrogen generation. The enhanced HER performances are ascribed to the synergistic effects between Bi2S3 and MoS2, giving rise to large electrocatalytic active area and fast HER kinetics. The results pave a new path to design and construct excellent Bi2S3/MoS2 nanomaterials for electrocatalytic hydrogen generation. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.