In this talk, we investigate an inverse scattering problem of determining unknown scatterers from time-dependent acoustic measurements. A novel time-domain direct sampling method is developed to determine the location and shape of inhomogeneous media. This approach is easy to implement since only space-time integrations are involved in the evaluation of the imaging functionals. Using the Fourier-Laplace transform, we establish an inherent connection between the time-domain and frequency-domain direct sampling methods. Several numerical examples will be provided to illustrate the effectiveness of the proposed method.