<p>In this paper, we study the discretization of free scalar quantum field theory using the Haar wavelet basis. The field operators are expanded in an orthonormal multi-resolution system and the expansion is truncated at finite resolution, with this application a finite-dimensional representation of the Hamiltonian is obtained. These procedures turn the operator in a form of quadratic Hamiltonian that describes a set of coupled harmonic oscillators. This construction provides an explicit realization of ultraviolet and infrared cutoffs within a wavelet framework also the basis functions preserve their orthogonality and spatial localization. The Haar wavelet basis has a property of compact support which allows a transparent implementation of the discretization procedure. Using this property we can create a matrix formulation suitable for numerical diagonalization. We analyze the structure of the discretized Hamiltonian and comment on how locality and symmetry considerations are affected by the Haar approximation, and identify the spectral implications of the nearest-neighbor coupling structure. We use the results to show how multiresolution techniques can be used as a constructive discretization scheme in quantum field theory and clarify both the practical advantages and intrinsic limitations of the Haar basis in this context.</p>