From　the　viewpoint　of　fracture　mechanics,　of　importance　is　the　near-tip　field　which　can　be　characterized　as　field　intensity　factors.　In　this　paper,　the　crack-tip　field　intensity　factors　of　the　stress　and　electric　displacement　in　two　dimensional　piezoelectric　solids　are　evaluated　by　using　four　approaches　including　the　displacement　extrapolation,　the　stress　method,　the　J-integral　and　the　modified　crack　closure　integral　method　(MCCI)　based　on　a　boundary　element　method　(BEM).　The　strongly　singular　displacement　boundary　integral　equations　(BIEs)　are　applied　on　the　external　boundary　of　the　cracked　solid,　while　the　hypersingular　traction　BIEs　are　used　on　the　crack　faces.　Three　numerical　examples　are　presented　to　show　the　path　independence　and　the　high　accuracy　of　the　J-integral　in　piezoelectric　materials　and　to　analyze　the　pros　and　cons　of　these　approaches　in　evaluating　the　field　intensity　factors.