Nickel sulfide (Ni3S4) has been recognized as one of the most advanced anode materials for sodium-ion batteries (SIBs) on account of its cost effectiveness, commendable redox reversibility and high theoretical capability. However, like other metal sulfide (MS) anodes, the Ni3S4 suffers from poor cycle life and inferior rate capability owing to large volume changes during the repeated Na+ de/insertion process and unsatisfied electronic conductivity. Herein, we fabricated porous Ni3S4/carbon aerogels (Ni3S4/CAs) using carrageenan-Ni hydrogels as the precursor via the pyrolysis route. The sulfate groups located uniformity and confinement for Ni2+ ions in carrageenan double-helix structures converted into uniform Ni3S4 nanoparticles (NPs) embedded in porous carbon through the decomposition. Remarkably, the as-prepared Ni3S4/CAs-1 sample as the anode material for SIBs exhibits a high reversible capacity of 297 mAh g−1 at a current density of 1 A g−1 after 100 cycles. This work develops a facile way to synthesize Ni3S4/CAs as a promising anode material for SIBs from marine biomass resources.