In　this　paper,　a　universal　matrix-form　displacement　extrapolation　formula　and　the　explicit　form　are　derived　to　determine　the　dynamic　intensity　factors　of　an　interface　crack　in　general　anisotropic　piezoelectric　bi-materials.　It　is　very　feasible　for　numerical　methods,　especially　for　boundary　element　method　(BEM)　which　can　directly　present　the　unknown　boundary　values.　Using　the　explicit　extrapolation　formula,　the　transient　response　of　interfacial　cracks　in　piezoelectric　bi-materials　under　electro-mechanical　impacts　is　studied　by　time-domain　BEM　together　with　a　sub-domain　technique.　The　present　time-domain　BEM　uses　a　quadrature　formula　for　the　temporal　discretization　to　approximate　the　convolution　integrals　and　a　collocation　method　for　the　spatial　discretization.　Quadratic　quarter-point　elements　are　implemented　at　the　tips　of　the　interface　cracks.　General　cases　for　the　poling　axis　of　each　piezoelectric　component　unparallel　to　the　Cartesian　coordinate　axes　are　studied.　Numerical　examples　are　presented　and　discussed　the　effects　of　the　poling　direction,　material　combination　and　the　load　combination　on　dynamic　intensity　factors.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.