Piezoelectrics　are　often　subjected　to　cyclic　loads　during　service,　leading　to　the　occurrence　of　fatigue　fracture.　Traditional　models　typically　employ　the　ideal　electric　boundary　conditions　to　describe　the　distribution　of　electric　field　on　crack　faces,　which　may　fail　to　accurately　reflect　the　influence　of　electric　properties　on　the　fatigue　life　of　piezoelectrics.　In　this　work,　a　phase-field　model　for　fatigue　crack　growth　in　piezoelectrics　is　proposed.　By　constructing　the　suitable　degradation　function,　the　energetically　consistent　boundary　condition　(ECBC)　is　involved　in　the　present　model.　The　ECBC　considers　the　effect　of　crack-filled　mediums　on　electric　properties,　allowing　for　a　more　accurate　description　of　electric　characteristics　on　crack　faces.　Numerical　simulations　are　performed　to　investigate　the　effects　of　the　electric　boundary　condition　and　external　electric　field　on　fatigue　behaviors　of　piezoelectrics.　The　medium　within　the　crack　may　significantly　affect　the　fatigue　life　of　piezoelectrics.　The　higher　the　relative　dielectric　constant　of　the　ECBC,　the　closer　the　predicted　fatigue　life　is　to　the　situation　under　electrically　permeable　boundary　condition.　The　present　study　may　provide　theoretical　tool　for　assessing　the　lifetime　of　piezoelectrics.