Euphausia superba is a highly stocked biological resource, while its utilization in producing shrimp sauce is rarely reported. Traditional fermentation methods of seafood sauces usually need long fermentation period. This study proposed a rapid fermentation method for Euphausia superba sauce (AKS) and verified the feasibility, then revealed the key flavor substances and functional core microorganisms and established their relationship. Results showed that the rapidly fermented AKS owned the amino acid nitrogen content of 1.10 g/100 mL, the total nitrogen of 15.21 %, the volatile base nitrogen of 63.94 mg N/100 g, and the liquefaction rate of 87 %. Asp, Glu, Thr, GMP, malic acid, acetic acid, lactic acid, methanethiol, pentanal, propanal, etc. were screened out as the key flavor compounds. Peptoniphilus, Halomonas, Paenochrobactrum, Proteus, etc. were picked out as the core microorganisms. Further analysis revealed that Paenochrobactrum, Halomonas, Erysipelothrix, Aquamicrobium and Leucobacter were involved in the generation of free amino acids, organic acids, aldehydes and ketones. This study provided a reference for the rapid fermentation of AKS during industrial production, laying the foundation for effective control fermentation process and ensuring quality stability of prepared AKS.