It is demonstrated that the wavelets can be used to considerably speed up simulations of the wave packet propagation in multiscale systems. Extremely high efficiency is obtained in the representation of both bound and continuum states. The new method is compared with the fast Fourier algorithm. Depending on ratios of typical scales of a quantum system in question, the wavelet method appears to be faster by a few orders of magnitude.1. Owing to the fast development of the computational tools the direct solution of the time-dependent Schroedinger equation has become one of the basic approaches to study the evolution of quantum systems. Thus, the wave packet propagation (WPP) method is successfully applied to time dependent and time-independent problems in gas-surface interactions, molecular and atomic physics, and quantum chemistry [1,2,3,4]. One of the main issues of the numerical approaches to the time-dependent Schroedinger equation is the representation of the wave function |Ψ(t) of the system. Development of the pseudospectral global grid representation approaches yielded a very efficient way to tackle this problem. The discrete variable representation (DVR) [5] and the Fourier grid Hamiltonian method (FGH) [6,7] have been widely used in time-dependent molecular dynamics [1,2,8], S-matrix [9,10] or eigenvalue [11] calculations. The FGH method based on the Fast Fourier Transform (FFT) algorithm is especially popular. This is because for the mesh of N points the evaluation of the kinetic energy operator requires only NlogN operations and can be easily implemented numerically. In the standard FGH method the wave function is represented on a grid of equidistant point in coordinate and momentum space. It is well suited when the the local de Broglie wavelength does not change much over the physical region spanned by the wave function of the system [11]. There are, however, lot of examples where the system under consideration spans the physical regions with very different properties. Consider, for example, the scattering of a slow particle on a narrow and deep potential well. Despite the short wave lengths occur only in the well, in the FGH method they would determine the lattice mesh over entire physical space leading to high computational cost. In fact, pseudospectral global grid representation approaches are difficult to use in multiscale problems. This is why much of work has been devoted recently to the development of the mapping procedures in order to enhance sampling efficiency in the regions of the rapid variation of the wave function [8,11,12,13,14,15]. Though mapping procedure, based on the variable change x = f (ξ) is very efficient in 1D, it is far from being universal. One obvious drawback 1 is that it is difficult to implement in higher dimensions. In the case of several variables, there is no simple procedure to define the mapping functions f so that the lattice would be fine only in some designated regions of space. Next, the topology of the new coordinate surfaces can be different from that ...