Objective： A strain of Lactococcus lactis subsp. lactis， named as IMAU11823， was isolated from natural fermented dairy products Jiaokou in Xilin Gol League of Inner Mongolia， which expressed excellent fermentation characteristics and capacity of exopolysaccharide（EPS） production. In this present study， whole genome sequencing of this strain was performed to analyze the mechanisms of EPS production. Methods： The genome of this strain was generated by the PacBio SMRT sequencing technique， then the assembly， prediction and annotation of the genome were carried out in a series of bioinformatics methods. The genes related to the EPS biosynthesis were furtherly explored. Results： In the strain L. lactis subsp. lactis IMAU11823， a single circular chromosome （2 458 520 bp） and three circular plasmids （127 965， 24 554， 7 734 bp） were detected. The GC content of the genome and plasmids were 35.2%， 35.7%， 39.5% and 32.7%， respectively. Furtherly， genes associated with the transport system of lactose， cellobiose， sucrose， fructose， mannose and galactose， as well as biosynthesis of seven sugar nucleotides were annotated in IMAU11823 genome. Besides， an eps gene cluster epsRXCDBEF （GTF1） H （GTF2） JKM involved in EPS biosynthesis was also predicted. Conclusion： The present study revealed the genomic characteristics and the potential mechanisms for the EPS synthesis of L. lactis subsp. lactis IMAU11823， which could provide a theoretical basis for the structural characteristics of EPS and laying a theoretical foundation for the strain in the industrial application.