In this work coarse-graind (CG) potentials for Poly(ethylene terephthalat) (PET) were constructed from atomistic simulation of short PET chains via iterative Boltzman inversion (IBI) method. Three mapping schemes were taken into account to construct three CG models. The CG potentials were then employed to simulate long PET chains (200 chemical repeat units). From the result of CG simulation we have calculated the density, the average chain end-to-end distance, the relaxation time for end-to-end distance and the center of mass mean square displacements. The results show that the CG models well describe the structural properties of PET , but the dynamics accelerate artificially.