B cells express B-cell receptors (BCRs) which recognize antigen to trigger signaling cascades for B-cell activation and subsequent antibody production.BCR activation has a crucial influence on B-cell fate.How BCR is activated upon encountering antigen remains to be solved,although tremendous progresses have been achieved in the past few years.Here,we summarize the models that have been proposed to explain BCR activation,including the cross-linking model,the conformation-induced oligomerization model,the dissociation activation model,and the conformational change model.Especially,we elucidate the partially resolved structures of antibodies and/or BCRs by far and discusse how these current structural and further immunogenomic messages and more importantly the future studies may shed light on the explanation of BCR activation and the relevant diseases in the case of dysregulation.