Marine snow represents nutrient-rich habitats for microbial communities in marine environments. Microbial transformation and remineralization of marine snow detritus play an essential role in the marine carbon cycle by exporting organic carbon from the coast to the pelagic ocean, yet the physiological mechanism of microbes’ cleavage on marine snow particles remains largely unclear. Here, we combined metagenomic and –proteomic analysis to explore the taxonomic and functional profile of microbes responding to a simulated marine snow system. Our results showed that microbial metabolism was more dynamic in the metaproteome than the metagenome as a response to marine snow particles and Gammaproteobacteria was the major taxon initially utilizing marine snow. The production of carbohydrate-active enzymes (CAZymes) and transporters facilitated the consumption and assimilation of marine snow particles; however, niche separation at both taxonomic and functional levels was observed. Metagenomic assembly genome (MAG) results showed Alteromonas, Vibrio and Thalassotalea species were the major species consuming marine snow but exhibited distinct lifestyles which led to niche separation between particle-attached (PA) and free-living (FL) ones. Although chemotaxis protein and motility protein were enriched in the metabolism of both FL and PA MAGs, the type of transporter proteins was the reason for such niche separation, where ATP-binding cassette transporters (ABCTs) were predominant in Vibrio MAGs in the FL fraction but TonB-dependent outer membrane transporters (TBDTs) were mainly used by Thalassotalea MAGs in the PA fraction. In contrast, Alteromonas MAGs were abundant in both FL and PA fractions, implying a leading role in marine snow degradation, which cleaved marine snow aggregates into fragments by using CAZymes to directly provide available compounds for others. Taking together, our results identified the key metabolism utilized by microbes for marine snow scavenging and highlighted potential carbon sequestration mechanisms from coastal seawaters to the open ocean.