Aiming　at　wide　range　nondestructive　testing　of　plate　structure,　the　technique　of　Lamb　wave　transducer　array　based　on　software　virtual　focusing　is　developed,　i.e.　based　on　the　principle　of　equiphase　superposition　in　the　phased　array,　through　the　software　processing　of　the　data　received　by　the　array,　the　directional　focusing　of　beam　of　array　is　implemented　without　needing　for　hardware　system　of　phase　control.　By　using　the　simulation　data,　the　influences　of　diameter　of　array,　number　of　array　elements　and　number　of　beams　on　the　circumferential　resolution　and　side　lobe　noise　of　virtual　focusing　image　are　studied.　It　is　found　that　the　spacing　of　array　elements　should　be　smaller　than　half-wavelength　of　Lamb　waves　in　order　to　avoid　the　obvious　side　lobe　noise.　Lamb　wave　experiments　are　conducted　for　detecting　the　plate　structure　by　using　array　of　electromagnetic　acoustic　transducer　(EMAT).　The　results　show　that　by　selecting　appropriate　diameter　of　array,　number　of　array　elements　and　number　of　beams,　and　through　virtual　focusing　processing　of　the　signals　detected　by　the　transducer　array,　defect　detection　and　identification　of　structural　features　of　plate　in　any　direction　(such　as　boundary)　can　be　realized.　©　2011　Journal　of　Mechanical　Engineering.