In　this　article,　the　elastodynamic　problems　are　investigated　within　the　framework　of　a　consistent　couple-stress　theory　(CCST).　The　basic　equations　for　the　CCST　elastodynamic　problems　are　derived　at　first.　These　dynamic　formulas　are　then　analyzed　in　the　frequency　domain　by　the　Fourier　transform.　The　frequency-domain　fundamental　solutions　to　the　transformed　elastodynamic　problems　are　subsequently　derived　for　the　two-dimensional　(2D)　plane-strain　state.　Based　on　the　fundamental　solutions　and　the　elastodynamic　reciprocal　theorem,　the　frequency-domain　boundary　integral　equations　(BIEs)　are　established.　Then,　the　BIEs　are　numerically　solved　by　a　collocation　method　in　conjunction　with　analytical　and　numerical　treatments　of　the　arising　singular　integrals.　To　obtain　the　time-domain　dynamic　responses,　an　exponential　window　method　(EWM)　is　adopted　to　transform　the　frequency-domain　results　to　the　time-domain　solutions.　By　using　the　developed　boundary　element　method　(BEM),　several　typical　couple-stress　elastodynamic　problems　are　numerically　investigated　and　the　size-effects　are　studied　by　using　different　values　of　the　length-scale　parameter　in　the　CCST.　Good　agreements　between　the　results　obtained　by　the　developed　BEM　for　a　tiny　length-scale　parameter　and　the　corresponding　classical　BEM　results　or　analytical　solutions　are　achieved,　which　validates　the　high　accuracy　of　the　present　BEM.