Receptor kinse BAK1 (BRI-Associated Kinase 1) has been highlighted among all of 610 RKs of Arabidopsis thaliana because it played different independent roles in multiple signal transduction pathways.BAK1 is a typical leucine-rich repeats receptor kinase(LRR-RK) that belongs to the LRR-RKⅡ family and structurely composed with three parts named extracellular domain,transmembrane domain and intracellular kinase domain.BAK1 was firstly identified as a dual co-receptor of BRI1 and FLS2,mediating BR signaling and pathogen-associated molecular pattern (PAMP) triggered immunity (PTI) in plant,respectively.Additionally,a set of new BAK1- interaction protein components,such as EFR,AvrPto,PEPR 1/2,PUB13,BIR1,BON1,have been uncovered recently.This work has comprehensively reviewed the recently research progress on the molecular structure of BAK1,function-redundance of SERK,the role of BAK1 involving in BR signaling and PTI,as well as cell death,and expectively to clarify the research questions presently faced.