We　design　an　A-B　interferometer　with　a　＂single　quantum　dot　atom＂　embedded　in　the　upper　arm　and　a　＂double　quantum　dot　molecule＂　embedded　in　the　lower　arm.　The　transmission　coefficient　and　average　current　characteristics　are　studied　as　the　time-dependent　external　field　is　introduced.　When　the　interdot　coupling　strength　is　weak,　the　change　of　Rashba　spin　orbit　coupling　strength　has　a　strong　influence　on　the　spin　transmission　coefficient.　When　the　interdot　coupling　strength　and　Rashba　spin　orbit　coupling　strength　take　appropriate　values,　the　spin　up　and　spin　down　transmission　coefficients　completely　coincide,　and　a　resonance　band　emerges　at　the　Fermi　level.　The　spin　polarization　can　be　close　to　+1　or　-1　by　adjusting　the　Zeeman　magnetic　field,　the　interdot　coupling　strength,　and　the　gate　voltage.　In　the　presence　of　photon　assistance,　the　spin　polarization　changes　periodically　in　a　certain　proportion,　so　as　to　realize　the　spin-polarized　transport　with　controllable　time-dependent　external　field.　These　findings　provide　a　theoretical　basis　for　the　spin　polarized　function　of　A-B　interferometer.