Analysis　of　the　crack-tip　amplification　and　shielding　by　micro-cracks　in　an　unbounded　two-dimensional　piezoelectric　solid　is　presented　in　this　paper.　A　boundary　element　method　(BEM)　based　on　the　hypersingular　traction　boundary　integral　equations　(BIEs)　is　developed　for　this　purpose.　Integrals　with　hypersingular　kernels　are　analytically　transformed　into　weakly　singular　and　regular　integrals.　A　collocation　method　is　applied　for　the　spatial　discretization.　Quadratic　quarter-point　elements　are　implemented　at　all　crack-tips.　The　amplification　ratios　of　the　field　intensity　factors　and　mechanical　strain　or　electrical　energy　release　rate　are　defined　to　show　the　crack-tip　amplification　and　shielding.　Numerical　results　are　compared　with　the　analytical　results　for　isotropic　materials　to　verify　the　present　BEM.　The　influences　of　various　loading　conditions,　the　location　and　orientation　angles　of　micro-cracks　on　the　amplification　ratios　are　investigated.　The　contours　of　the　amplification　ratios　for　an　arbitrarily　located　micro-crack　are　also　presented　to　show　the　crack-tip　amplification　and　shielding　effects.　(C)　2013　Elsevier　Ltd.　All　rights　reserved.