Resistance　spot　welding　of　the　zinc-coated　high　strength　steel　sheet　is　widely　used　with　increasing　demands　for　higher　fuel　efficiency　and　the　safety　requirement　in　automobiles.　However,　tiny　fluctuation　in　welding　parameters　will　lead　to　quality　deficient　such　as　stick　weld,　deficient　diameter　and　spatter　due　to　the　poor　weldability　of　the　high　strength　steel　and　the　adverse　influences　of　the　coated　zinc.　Ultrasonic　testing　(UT)　is　recognized　as　a　promising　technology　in　estimating　the　quality　of　the　spot　welds.　Usually,　diameter　of　the　weld　spot　may　be　estimated　through　examining　the　ultrasonic　sequence　echo,　the　diameter　of　the　probe　should　be　the　same　as　that　of　the　regular　weld　spot　and　the　tester　must　possess　special　knowledge　on　the　ultrasonic　test.　Thus,　it　is　difficult　to　increase　the　testing　efficiency,　decrease　testing　cost　and　ensure　the　testing　reliability.　In　the　research,　the　Lamb　wave　was　adopted　to　test　the　spot　weld.　The　wave　mode　transformation　is　simplified　and　the　dispersion　phenomenon　is　obviously　decreased　by　using　an　ultrasonic　oblique　incidence　method.　Moreover,　the　attenuation,　sound　velocity　and　the　sound　components　are　investigated　in　theory　and　experiment.　Thereafter,　the　Lamb　wave　is　adopted　in　the　evaluation　on　spot　weld　quality　of　zinc-coated　high　strength　steel.　The　interactions　between　the　Lamb　wave　and　nugget　characters　such　as　diameter,　indentation,　columnar　crystals　are　investigated　and　the　relation　between　the　maximum　tension　load　and　ultrasonic　characteristic　amplitude　is　obtained.　The　technology　proposed　in　the　present　work　avoids　distinguish　the　complex　wave　sequence　of　the　spot　weld　and　has　higher　sensitivity,　especially　for　stick　weld　compared　to　the　traditional　method.　Moreover,　the　testing　cost　and　requirements　of　the　testing　system　must　be　decreased　by　using　of　the　low　frequency　probe.　Meanwhile,　the　inaccessible　area　with　ultrasonic　impulse　echo　method　can　be　investigated　due　to　the　arrangement　of　the　probes.　Thus,　the　method　proposed　in　this　research　is　an　effective　nondestructive　evaluation　method　for　spot　welds　of　coated　high　strength　steel　sheet.