Aiming　at　the　influence　of　multi-mode　phenomenon　on　the　defect　detection　performance　in　Lamb　wave　detection,　in　this　paper　the　linear　array　single-mode　Lamb　wave　selection　method　is　studied.　Based　on　the　theoretical　analysis　of　linear　array　Lamb　wave　propagation　issue　in　infinite　plate,　a　linear　array　single-mode　Lamb　wave　selection　method　based　on　genetic　algorithm　is　developed.　Under　the　condition　of　keeping　the　linear　array　excitation　amplitudes　identical,　the　optimized　time　delays　are　applied　to　the　elements　of　the　linear　array,　therefore　a　single　mode　Lamb　wave　excitation　is　realized.　Moreover,　the　influence　of　excitation　frequency　on　linear　array　Lamb　wave　mode　selection　is　studied,　and　the　detection　frequency　for　optimal　single　mode　selection　is　obtained.　The　simulation　and　detection　experiment　results　show　that　single　A0　and　S0　mode　detection　can　be　realized　through　controlling　the　excitation　time　delays　of　linear　array　elements.　The　research　work　provides　a　feasible　technical　means　for　the　mode　selection　of　ultrasonic　guided　wave.　©　2018,　Science　Press.　All　right　reserved.