Abstract: This paper put forward using Wavelet Instantaneous Parameter Methods (WIPM) and the modulus maxima method of the Wavelet Transform(WTM),respectively, for time delay estimations of narrow-band and wide-band multi-mode(A₀ and S₀)Lamb waves.The methods are much higher resolution than Hilbert Instantaneous Parameter Methods(HIPM). WTM's resolution is the highest;WIPM's resolution is the second; and HIPM can not magnificently estimate the multi-mode time delay.Synchronously this paper puts forward the method of the reconstruction based on wavelet Transform modulus maxima to estimate attenuation coefficient of multi-mode ultrasonic Lamb wave A₀ and S₀. And the method indicated by experiment results is feasible for metal aluminum thin plate.