Abstract: The chemical shifts and the spin-spin coupling constants of high-resolution NMR spectra of some three-, four-spin cases are caculated by using the trial-and-error method of the Euclidean Norm of Hamiltonian matrix. In this method., the experimental energy levels are used as the zero-order approximation of the Hamiltonian matrix so that the trouble of selecting primary chemical shifts and spin-spin coupling constants is avoided and only one resolution can be obtained