The dispersive characteristics of higher order mode Lamb waves(HOMLW) excited by interdigital transducers(IDT) were measured and analyzed,which were necessary for designing microsensor in ultrahigh frequency(VHF).A measurement system was set up,in which dispersive characteristics of HOMLW were obtained by the method of transform between frequency and time domains.The characteristics of amplitudefrequency and phasefrequency of Lamb wave were automeasured by the system.By IFFT,the pulse response of the IDT device was obtained.Different modes were separated in time domain and dispersive curve of each mode was calculated by FFT.The phase velocity of HOMLW is greater than the surface wave(SAW) velocity and an oscillator in higher frequency could be made,so the absolute sensitivity of microsensor could be increased.