To　determine　fracture　parameters　of　interfacial　cracks　in　transverse　isotropic　magnetoelectroelastic　composites,　a　displacement　extrapolation　formula　was　derived.　The　matrix-form　formula　can　be　applicable　for　both　material　components　with　arbitrary　poling　directions.　The　corresponding　explicit　expression　of　this　formula　was　obtained　for　each　poling　direction　normal　to　the　crack　plane.　This　displacement　extrapolation　formula　is　only　related　to　the　boundary　quantities　of　the　extended　crack　opening　displacements　across　crack　faces,　which　is　convenient　for　numerical　applications,　especially　for　BEM.Meantime,　an　alternative　extrapolation　formula　based　on　the　pathindependent　J-integral　and　displacement　ratios　was　presented　which　may　be　more　adaptable　for　any　domainbased　numerical　techniques　like　FEM.　A　numerical　example　was　presented　to　show　the　correctness　of　these　formulae.　©　2015　Jun　Lei　et　al.,　licensee　De　Gruyter　Open.