In　this　study,　a　bioactive　peptide　YGPSSYGYG　(YG-9)　with　immunomodulatory　activity　was　isolated　and　identified　from　Pseudostellaria　heterophylla　protein　hydrolysate.　The　highest　proliferation　index　of　mouse　spleen　lymphocytes　reached　1.19　in　the　presence　of　50　mu　g/mL　YG-9.　YG-9　could　activate　RAW264.7　cells　by　promoting　the　secretions　of　NO,　the　pinocytosis　activity,　and　the　productions　of　ROS　and　TNF-alpha.　Moreover,　YG-9　enhanced　the　expressions　of　TLR2　and　TLR4　in　RAW264.7　cells.　TNF-alpha　secretions　induced　by　YG-9　were　reduced　in　TLR2　and　TLR4　siRNAs　knockdown　cells,　and　this　suggested　that　macrophage　activation　of　YG-9　was　through　TLR2　and　TLR4.　Furthermore,　YG-9　promoted　the　translocation　of　NF-kappa　B　through　the　acceleration　of　I　kappa　B-alpha　phosphorylation　and　degradation.　Also,　TNF-alpha　secretions　promoted　by　YG-9　were　inhibited　by　NF-kappa　B-specific　inhibitors　pyrrolidine　dithiocarbamate　and　BAY11-7082.　Altogether,　these　results　suggested　YG-9　activated　RAW264.7　cells　via　the　TLRs/NF-kappa　B/TNF-alpha　signaling　pathway.