The　interaction　of　Lamb　wave　A(0)　mode　with　delamination　and　delamination　detection　in　16-ply　carbon　fiber-reinforced　epoxy　composite　beams　are　investigated　through　three-dimensional　finite　element　simulation　and　experimental　studies　in　this　article.　Wave　propagation　in　composite　beams　with　delamination　with　different　lengths　and　located　at　different　interfaces　are　investigated　in　finite　element　simulations,　and　some　unique　mechanisms　of　interaction　between　A(0)　mode　and　delamination　are　revealed　in　detail.　Experimental　results　obtained　with　air-coupled　ultrasonic　transducers　are　well　in　accordance　with　finite　element　simulation　results.　In　an　experimental　study,　an　air-coupled　ultrasonic　transducer　is　oriented　at　a　coincidence　angle　such　that　it　generates　a　pure　fundamental　antisymmetric　Lamb　wave　mode　A(0)　for　delamination　detection　in　laminated　composite　beams.　The　receiving　transducer　can　be　oriented　either　to　detect　the　transmitted　wave　propagating　in　the　same　direction　as　incident　wave　or　to　detect　the　reflected　wave　in　contrast　to　incident　wave.　The　location　and　size　of　delamination　can　be　evaluated　quantitatively　using　the　time-of-flight　of　reflected　wave　from　both　ends　of　the　delamination.