Toll like receptors(TLRs)can recognize pathogen-associated molecular patterns and raise the adaptor protein molecules containing toll IL-1 receptor(TIR)domain.Moreover,TLRs can initiate specific immune response through activating signal transduction by the MyD88-dependent pathway or TRIF-dependent pathways.This article summarizes the latest research review on structure features,distribution,ligand recognition,adaptor protein molecules participating in signal transduction and signal transduction pathway of TLRs.