Dynamics of the polymeric media being in a plastic condition is described within the limits of rheological model of a nonlinear viscoelastic fluid with one tensor internal thermodynamic parameter. The system of the equations of preservation is written down in the assumption of absence of secondary flows and represents system of seven partial differential equations of the first order. As a result of the decision of this system the velocity profile and components of stress tensor as functions of a point of space and rheological parameters of a polymeric fluid have been found.