In this article, we consider 2D second grade fluid equations in exterior domain with Dirichlet boundary conditions. For initial data u0 ∈ H 3 (Ω), the system is shown to be global well-posed. Furthermore, for arbitrary T > 0 and s ≥ 3, we prove that the solution belongs to L ∞ ([0, T ]; H s (Ω)) provided that u0 is in H s (Ω).