Abstract: In the area of internal inclusion detection using ultrasonic,identifying the location and type of internal inclusions using the collected back echo signals has always been a difficult problem. A two-dimensional metallic plate containing inclusions is established. Ultrasonic wave fields inside this material are calculated by the finite element method. Echo waves for two typical inclusions of Al₂O₃ and TiN and for these inclusions with different depths are obtained. The influences of the type and depth of inclusions on the time-domain and the spectral distribution of interfacial waves,echo waves of inclusions and bottom echo waves are analyzed especially.