The poly(ethylene oxide) (PEO) is employed as one typical example to demonstrate a new multiscale modeling scheme for simulating high‐molecular‐weight polymeric melts. In this scheme, the structural distributions and the densities at five elevated temperatures at 1 atm, which are obtained from molecular dynamics (MD) simulations of all‐atomistic oligomeric melt, are employed as the target functions to parameterize the coarse‐grained (CG) potentials. The extensive CG MD simulations reproduce the densities at a wide temperature range, from which the glass transition temperatures (Tg) and the volumetric expansion coefficients can be determined for the PEO bulks. These results confirm that the so‐developed CG potentials exhibit excellent chain‐length and temperature transferability. Furthermore, some essential structural properties and dynamics speedup features are captured, and the latter qualitatively dictates the agreement in Tg. Such a scheme can play an important role in predicting thermomechanical properties of specific complex polymers.