To　excite　the　single　Lamb　wave　mode　for　non-destructive　detection　in　plates,　a　low　frequency　piezoelectric　transducer　for　exciting　single-mode　Lamb　wave　is　designed.　Based　on　theoretical　model　and　finite　element　simulation　model,　the　frequency　response　of　piezoelectricity　transducer　is　investigated.　The　influence　of　the　parameters　of　backing　mass　and　interface,　such　as　thickness,　density　and　elastic　modulus　are　foused.　Meanwhile,　the　performance　testing　of　piezoelectric　transducers　with　different　structural　parameters　are　conducted.　The　influences　of　parameters　of　transducer　to　the　frequency　characteristics　and　excitation　waveform　are　investigated.　As　a　result,　a　piezoelectric　transducer　is　designed　to　excite　low-frequency　A0　mode　Lamb　wave　in　plates.　The　designed　piezoelectric　transducers　are　constituted　into　array　for　non-destructive　testing　in　plates.