Abstract: The problem of ultrasound attenuation in the semiconductor which has a quantum well structure with infinite potential barriers has been studied，in the case of the acoustic lattice vibrations interacting with impurity centers in the presence of an exciting laser field. The electron transitions from an acceptor- impurity band to the first quantized energy level of the conduction band occurs in the external laser field，which is forbidden in the absence of the external high frequency field,and the external laser field supply the energy deficit for the electron to make the transition to absorb the acoustic phonon.The total ultrasound absorption coefficient has been calculated by applying second-order perturbation theory,and specialized for the case of GaAs/AlGaAs quantum well sample. It has been found that is a fairly large quantity as compared with its value in bulk as the well width decreases from values corresponding to the almost bulk situation.