We successfully applied a multiscale simulation method to a spinning process of a well-entangled polymer melt. In the spinning process, the macroscopic dynamics of the polymer melt and microscopic states of polymer chains are tightly connected through the strain rate and stress fields. A macroscopic model for the spinning process is constructed by using the standard and simplified 1D approach, thus ignoring the complex flow conditions near the die exit. In our multiscale simulation method, to evaluate the flow history of the stress, we employ a particle method in the Lagrangian manner at the macroscopic level and use the slip -link model to address entangled polymer dynamics at the microscopic level. Therefore, we can take into account the history effect of polymer melts and quantitatively evaluate the polymer dynamics, such as the entanglements. From our multiscale simulations, the number of entanglements decreases with flow down the spinning line because of the convective constraint release (CCR) effect. Moreover, we found that the number of entanglements generally decreases in the middle section of a polymer chain. This result shows that our multiscale simulation makes it possible to design a polymer melt that has desirable physical properties for producing a sophisticated fiber. (C) 2017 Elsevier B.V. All rights reserved.