We examine the one-dimensional (ID) d-p model in comparison with typical 1D models such as the 1D Hubbard model and the 1D t-J model using the numerical diagonalization method combined with the Luttinger liquid theory. We calculate the spin velocity nu(sigma), the charge velocity nu(rho) and the Luttinger liquid parameter K-rho for each model. Using these parameters, a relationship between the models is obtained unambiguously. We find that the d-p model can be described by the Hubbard model in the wide parameter region, while it can be described by the t-J model only in the strong coupling limit. (C) 2003 Elsevier Science B.V. All rights reserved.