We study models of dilute rigid rod-like polymer solutions. We establish the global wellposedness the Doi model for large data, and for arbitrarily large viscous stress parameter. The main ingredient in the proof is the fact that the viscous stress adds dissipation to high derivatives of velocity. * joonhyun@math.princeton.edu Notion of the solution. For the notion of solution, we follow the argument in [15]. By focusing on the evolution of macroscopic variables (trigonometric moments in this case), we can set up well-posedness of strong solutions for large class of initial data. In particular, higher regularity of Fokker-Planck equation is not necessary, and weak solution for Fokker-Planck equation is sufficient. On the other hand, since the effect of polymer to the flow are characterized by stresses, which are moments in (Doi), requiring spatial regularity for appropriate moments is necessary. In this regard, we introduce a terminology: for any n ∈ Z >0 , we let M n (x, t) := M I n (x, t) I:|I|=n := S 1 m I f (x, t, m)dm I:|I|=n (Moment)