A　time-domain　boundary　element　method　(BEM)　together　with　the　sub-domain　technique　is　applied　to　study　transient　response　of　interfacial　cracks　in　piecewise　homogeneous,　anisotropic　and　linear　piezoelectric　bi-materials　under　electrical　and　mechanical　impacts.　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.　To　determine　the　real　or　complex　dynamic　stress　intensity　factors　and　the　dynamic　electrical　displacement　intensity　factor　of　the　interfacial　cracks,　an　explicit　extrapolating　formula　in　a　typical　state　of　the　crack　plane　perpendicular　to　the　poling　direction　is　presented　in　this　paper.　Numerical　examples　are　presented;　and　the　effects　of　the　load　combination　and　material　combination　on　dynamic　intensity　factors　and　dynamic　energy　release　rate　are　discussed.