The development of novel and effective probiotic encapsulation systems is imperative in light of the susceptibility of probiotics to the acidic and highly-concentrated bile salts environment within the gastrointestinal tract. Carboxymethylated β-glucan (mGN) was utilized in this study to adhere to the surface of Lactococcus lactis (LL) through the bridging of a metal-phenolic network (Fe-TA)， aiming to achieve the single-cell encapsulation of LL (LL@Fe-TA@mGN) and assess the gastrointestinal stress resistance and intestinal retention capacity of LL@Fe-TA@mGN. The results demonstrated that the particle size and zeta-potential of LL@Fe-TA@mGN reached maximum values when 0.12 mg/mL mGN was applied， indicating the full encapsulation of LL at the single-cell level. No significant difference was observed for the growth curve between LL@Fe-TA@mGN and LL in the MRS medium， ruling out the potential toxicity of mGN. Both SEM and TEM clearly revealed the presence of a distinct ‘film’ layer on the surface of LL， providing further evidence that LL was encapsulated within the mGN. With the protection of mGN， the survival rate of LL@Fe-TA@mGN could be up to 14.63 and 1.94 times higher than that of bare LL after exposure to simulated gastric fluid and bile salts for 2 h， respectively. In vivo fluorescence imaging corroborated the prolonged intestinal retention ability of LL@Fe-TA@mGN. In summary， the single-cell encapsulation strategy we developed here could significantly enhance gastrointestinal resistance and prolong the intestinal retention of LL. These results offer novel insights for the development and application of probiotic encapsulation systems.