In　this　paper　the　elastic　properties　of　SiOx　film　are　investigated　quantitatively　for　local　fixed　point　and　qualitatively　for　overall　area　by　atomic　force　acoustic　microscopy　(A　FA　M)　in　which　the　sample　is　vibrated　at　the　ultrasonic　frequency　while　the　sample　surface　is　touched　and　scanned　with　the　tip　contacting　the　sample　respectively　for　fixed　point　and　continuous　measurements.　The　SiOx　films　on　the　silicon　wafers　are　prepared　by　the　plasma　enhanced　chemical　vapour　deposition　(PECVD).　The　local　contact　stiffness　of　the　tip-SiOx　film　is　calculated　from　the　contact　resonance　spectrum　measured　with　the　atomic　force　acoustic　microscopy.　Using　the　reference　approach,　indentation　modulus　of　SiOx　film　for　fixed　point　is　obtained.　The　images　of　cantilever　amplitude　are　also　visualized　and　analysed　when　the　SiOx　surface　is　excited　at　a　fixed　frequency.　The　results　show　that　the　acoustic　amplitude　images　can　reflect;　the　elastic　properties　of　the　sample.