The effect of a low concentration of salt and sugar on the quality and microbial succession in blunt snout bream (Megalobrama amblycephala) fillets was assessed by sensory analysis, total volatile basic nitrogen, biogenic amines, K value, total viable counts, 16S rRNA gene analysis, and Illumina MiSeq PE300 high-throughput sequencing. Fish samples were left untreated (control), treated with 1.8% salt (T1), or treated with 1.8% salt plus 0.9% sugar (T2). Consequently, salted and sugar-salted treatments extended the shelf life of bream fillets by 2 days, which retarded the increase of total volatile basic nitrogen, putrescine, cadaverine, and total viable counts. The putrescine and cadaverine concentrations of T2 were significantly (P < 0.05) higher than T1 after day 10. Brachybacterium was the major initial microbiota of bream fillets. As storage time progressed, Pseudomonas and Shewanella were major genera in the spoiled control group. Pseudomonas, Shewanella, and Pseudoalteromonas became the main spoilers in the T1 and T2 groups.