As　the　crystal　materials　are　applied　widely　in　the　fields　of　aerospace,　transportation,　electrical　and　electronic　engineering,　energy　and　environmental　protection,　the　new　requirements　for　the　researches　of　their　special　properties　and　testing　work　put　forward.　Based　on　the　constitutive　relationship　between　the　propagation　characteristic　of　acoustic　wave　in　materials　and　the　surface　wave　velocity,　an　acoustic　elasticity　theoretical　model　of　the　surface　acoustic　waves　(SAW)　velocities　of　silicon　crystal　contacting　with　its　elastic　constants　is　established.　The　theoretical　SAW　velocities　distribution　curves　of　different　crystallographic　planes　versus　azimuthal　angles　are　calculated　by　using　the　transformation　matrix.　Experimental　measurements　of　SAW　velocities　along　different　azimuthal　angles　of　three　crystallographic　planes　by　using　the　line　focusing　acoustic　transducer,　the　high-precision　defocusing　measurement　system　and　V　(f,　z)　analysis,　and　the　experimental　curves　of　SAW　velocities　are　consistent　with　the　theoretical　values.　It　proves　that　acoustic　microscopy　(AM)　technology　is　of　highly　accuracy　and　reliability　for　the　SAW　velocities　measurements　of　anisotropic　materials.　Meanwhile,　the　corresponding　consistency　between　the　crystal　structure　and　SAW　velocities　of　silicon　crystal　is　studied　further,　which　establishes　the　theoretical　basis　for　the　property　detections　and　evaluations　of　anisotropic　materials　including　silicon　crystal.　©　2018　Journal　of　Mechanical　Engineering.